I'm in a similar boat...I'm 6 weeks pregnant with my second (first lo is 2 years old). I found out a week ago that I'm pregnant after an ivf cycle. So far, not many symptoms - initially (even before the BFP), I felt twinges as if ligaments were tugging a bit around my uterus. I don't feel much of anything these days...a little tired last night and I must say I am always hungry (not an issue this early last time). I don't remember when the typical early symptoms started with my first, but I remember they were well established by 8 weeks. Initially I was comfortable with the fatigue and nausea not starting too quickly as I know it's going to be interesting with a toddler to contend with. But I think I'm ready for it, just for the reassurance. with ivf cycles, it's hard to trust sometimes that all will be fine, after weeks for feeling like your body needs so much help to do what seems so simple.
So you're not alone in wondering when things are going to pick up, and hey, maybe we'll both be lucky in not being too sick or tired this time. I hear it can differe a lot from one pregnancy to the next. I find I don't have the time like I did the first time to dwell on whether there's twinges, or symptoms as I'm too busy with my lo. So maybe I'm missing some of the subtle signs. Of course some signs are hard to ignore.
I'll also mention that I learned recently that milk production starts switching back to being more colostrum around 16 weeks gestation. So you may not see your lo reacting in terms of breastfeeding for a little while yet. A friend of mine who is still bf'ing and is also pregnant said her daughter started nursing less around 14 weeks or so, no change before then.