Two year old acting out while pregnant with #2

Is this a thing?

My son has always been really even tempered and happy. The last few months he’s been throwing tantrums, hitting, not listening and lately he’s been having changes in bowel habits not to be tmi.. like not going for days then having diarrhea..no other symptoms or diet changes and been a couple weeks. I know some of that’s just being two but I can’t help but feel like it’s my fault. I’m 36 weeks pregnant and tired and grumpy and def not able to hold him as much. He follows me around the house and cries if I won’t pick him up.. just new behavior for him!

Trying to tow the line of disciplining when hitting and such, but also giving lots of love and hugs when he’s feeling emotional. It’s tough