Anyone else?

Anyone ever had a pressure like feeling in your lower stomach? Where it doesn't hurt, just uncomfortable? I've had it for over 24 hours now & it's kinda scaring me. My period is 3 days late & I've been nauseous & tired. I've taken 2 pregnancy tests. The first one nothing showed up, probably bc I accidentally peed all over it bc I had to pee so bad & the second one I peed in a cup & dipped it in & did as the directions said & nothing showed on that one either. I'm going to get some more but just wondering about the pressure like feeling, wondering if anyone else can relate & tell me what it might be