fat or just pregnant 😂

I've been eating heaps and have gained 3-4 kg in 1 week (which usually never happens). 
I'm always feeling bloated and my tummy has gone bigger, and harder. 
I had my period 3 weeks ago and my partner did  cum while I was grinding on him (naked)- other than that, we've had protected sex. 
This is me previously - I've always had a flat stomach. Thoughts?? 
I haven't tried a pregnancy test last month before my period started and it came out negative. Can I try again? My period should start in 7 daysÂ