Hey there!
I have had the same thing, including in the TWW. I don;t know if it's because everything in there is a little more sensitive after already having a bub?
Anyway, had it 4-5 tims during TWW and have had it a few times since. I don't think it's too much to concern, but def speak to your DOC if you are worried.
I am not taking vitamins yet, but will soon.
I have had them so badthat I am doubled over, but they dont last for long, and usually after visiting the loo they are much better.

Good luck hun. I can safely say, they feel nothing like a m/c for me.

xxoo