Need some help!

Okay so I'm 14w&4d pregnant and I recently (past couple weeks) have been getting kinda nauseous after doing a lot of moving like if me and my SO have sex I get nauseous after wards or if I'm out walking a lot like at the mall I get nauseous after a little while can anyone please tell me what this could be? I googled it and Google says something about not enough blood flow to the stomach or that I'm over hydrated ( I do drink a lot of water but where I'm pregnant I'm always thirsty.) I know it's not morning sickness bc it only happens when I'm really active and I've also noticed that if I drink water while feeling nauseous it seems to help and keep me from throwing up.. Can someone please help me figure out what's happening? I plan to ask my Dr. tomorrow but just wanting some tips until then.