Did you ever find out what was wrong?
My 22 month old is the same way.
She has done this off and on since birth.
At first it was colic/acid reflux. We fixed this.
Then it started again months later, and we were told to use pepto. Bingo, it worked.
Then it started again a few months later and pepto worked only sometimes.
Now she is back to doing it again, around the same time of year as last year and nothing will stop her.
She cries to be picked up, she cries to be let down, she just cries and cries and screams. Pepto has been only fixing it 1/2 the time again, but it is daily (just like before) and goes on for a few weeks to a month or longer and then stops.
We never change her diet, (granted in years past we had to go Dairy free for her because of an allergy) and she never gets dairy. When she starts these fits we let her cry the appropriate amount of time and then go to her room to get her if she has not stopped. We tell her she can come out of her room, she screams "No" and cries louder. We have tried EVERYTING.
Once we get her from her room the fit will continue, sometimes for almost an hour. I always feel like I have a colicy toddler.
She does this in the middle of the night or aftr naps. I can not think of any times it happened early in the morning but there are times she wakes up a crab.
We tried seeing a specialist in dietary needs and there was nothing wrong with her.
We have been to her general Dr. several times.
No one can figure out what is going on, so I finally turned to google.
When she is not in these moods she is the happiest kid ever. As soon as the fit is over, she has a mild calm down period and then she is the happiest kid again.
Please let me know if you ever got answers.
In order for me to type everything here it would require several pages, but in general, I know there is something wrong and I can not solve this.