Okay, I happen to be something of an over-diagnoser. I am not hypochondriac and tend more to disbelieve something is wrong than assume it is wrong. Nonetheless I am big on learning about health, wellness, nutrition, development, etc. and maybe because I know SO much about what can cause issues I might be seeing more than is there. That being said, my kid does not seem 'normal' either. I don't know many kids well (like beyond a 2 hour playdate) so I have little perspective. So maybe you all can give me some?
My son is 4.5 and has always been somewhat intense. Nursed a lot until I weaned him at 25 months--he was still nursing every 2-3 hours, day and night. He started showing signs of 'giftedness' early on, like doing mental math at 2 and using advanced reasoning and language very early, too. Now at 4.5 he's clearly bright, but not reading or doing division or anything--then again he's not had much exposure and no lessons, educational (or any) TV, leapfrog, etc.
He's always been pretty high energy, but with the ability to also have stellar attention, sit quietly for an hour-long meal or a long book with few/no pictures. It's like his highs are higher, bigger, louder, etc while his times of calm and attention (at least at 2 or 3) were impressive for his age, now they seem average in that regard.
He feels others' emotions very keenly, if anyone is upset (even a baby we don't know crying at a restaurant, but especially if it's my husband or I) he gets angry, aggressive (not physically anymore, but his words and general energy are loud, hard, angry). He seems to have anxiety in certain situations, while being a very outgoing and social kid. Some kids cling to mom when unsure of a situation--he gets louder and more crazy, or angry even. Everyone within earshot knows when he's in a bad mood!
In the last several months he has been going through periods of what looks like OCD. At one point he had to pee every time he had even a sip of water, he still does that a little, but not as obsessively. Now he has to kiss himself constantly--by this I mean he kisses his fingertips and then touches the fingertips to various parts of his body. Some days it is only at story time and bedtime. Some days it is non-stop. Some days he does it to other things, too, like all over the grocery store. He is generally not upset while doing this, doesn't even seem to really notice he is doing it. When we call attention to it, it seems to get worse/more frequent. Sometimes he says he's kissing a boo boo (like if his leg barely brushes something) and other times he says he's cleaning himself/something else. He does not have any issues around cleanliness at all, loves to get dirty, wet, etc, No issues with clothing, tags, etc. Does not care about how things are arranged nor what order he gets dressed, where things go, how he eats his food. He eats anything and everything--all textures, mixed up or separate. Eggs cooked any way I do it. Does not care if others touch him, is a little more touchy-feeling than his peers, but not like he has to touch everyone all the time.
It does seem worse on grey/rainy days, when we don't get out or get physical as much, and when he's getting sick.
He's never been a great sleeper, waking up many times as a baby and toddler, and probably 3 times a night at 3 and 4--usually to pee and then go right back to sleep. He had some night terrors at 2.5 but only for a month or so. And then one every now and then since (like every few months). He asks if he's safe "Mommy, am I safe?" anytime he goes to another floor (alone) in our house, also when falling asleep. He does not sound or act scared at all when asking this.
I have had so many theories about what makes him worse or better. Lately salicylates *seem* to bother him when in high amounts, but I am already second guessing that as he's been low sals for a week and the last two days have been worse (it is also been grey/rainy for 2 days and we've been inside mostly).
Lastly, his diet is really clean and always has been--no artificial anything, no neurotoxins, traditional foods whole diet. He's had no vaccines, no antibiotics, no medications of any kind except homeopathics and herbs on occasion. He's never had any illnesses past a minor cold or self-limiting fever/virus. Hasn't even been to a doctor in over 2 years. He's tall and solid, never had digestive problems, never had skin problems, not a moment of reflux as a baby, never an ear infection or any known infection. Physically he is the picture of health. (we went gluten/grain-free last month and saw some improvement at first, but now not so much). He has been skin-prick tested for common food allergies--only very mild reaction to citrus, which we avoided for a year, reintroduced for a few months with unsure results, and now have removed in the last few weeks. He DID have some gluten on Saturday for the first time in 3.5 weeks, but he was fine Sunday, Monday and Tuesday. Wednesday started acting 'odd' again (with weather change).
Oh, and one more (important) thing--I suffer from generalized anxiety (self-diagnosed, but kind of a 'duh') that is well managed with diet/lifestyle, but his first few months I was having severe PP anxiety and I have had it mildly on and off since. Overall I am peaceful, happy, and calm, though. Maybe not as often as I'd like for his sake, though.
Thanks for any insight! This post is years in the making, I have been too nervous to put this much out there, be gentle!!
It sounds pretty borderline to me. Some of the things he's doing, I've seen my neurotypical kids do at different times in their lives. I know this sounds odd, but each of my boys have seemed at bit, well, strange, at that age! 
I don't know if that's just my kids or a developmental stage...the weird stage. But they would get a little obsessive about things or do weird body movements over and over again for a couple of weeks, then move on to something new. 
I think if you're concerned that I'd just keep an eye on things and see how it develops though. It's hard not to over analyse when dealing iwth our kids!
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