I promise I am not crazy!!!

So here is the deal. I have had my period like normal and the at home tests come back negative but some really weird stuff is happening. First, my boobs were super painful for like three weeks. Then I was nauseous. No big deal right? Here's the strange part. I swear I feel like something is moving in my stomach! I have one son and so I remember what it feels like but I'm unsure what to do. Also, I'm exhausted! My brain says no way that I can be pregnant but I just want to know if anyone has any ideas or has been through this...