Anyone feeling stretching/pulling sensation in lower abdomen?

I'm 12w2d (possibly 13w since baby keeps measuring 5 days ahead of my edd) and today I just have this weird pulling/pinching like sensation in my lower abdomen! My sister said its baby growing but it is so uncomfortable feeling! Almost like cramps but not... And it's making me feel sick as well as feeling like I have to use the bathroom more. Anyone else having this feeling and is it giving you side effects? I'm just a bit worried since this is my 1st as well as rainbow baby.