Minds playing tricks?

Reese
We just started TTC last week. We've talked about it a lot and we are both so excited for this journey. About 2 days after we started trying, I started feeling nauseous and tired. I am convinced my boobs are bigger. Could my mind just be messing with me because I am looking forward to this? Or could i be pregnant? I know it's not possible after trying for 3 days especially since we waited until I started tracking and got off my most recent period. Could I have been pregnant before we started intentionally trying and my last period was strangely light, a little late and very short. But again, I think I'm just anxiously awaiting. I am thinking about taking a test to confirm it or not. Have any of you ever psyched yourself out like this too?