Freaked out

Okay so literally in the span of maybe an hour this all went down. I did my nightly exercises and went to the bathroom to pee and then all of a sudden my stomach starts to twitch. I have never in my life had twitches in my stomach from exercise. Especially since I didn't do anything targeting those muscles. I have one 10 month old baby and these twitches feel like baby kicks. I recently got into a new relationship and I immediately think oh no I'm pregnant. We always use condoms and I have the Mirena so I know the chances are next to nil but I'm still like omg what if I'm that small chance. I drive up to the store grab a pregnancy test drive back home and take the test and it comes back negative. I'll probably take another in a week if I still feel the twitching but I think it's just involuntary muscle spasms at this point. It's also 12:20 am now.