No rude comments please I’m only 20 and new to this so please try to understand.

So I lost my virginity 4 months ago and since then my periods have been irregular. Since it was my first time (no condom and he didn’t cum in me) I had serious stress about it. After I had sex I got my periods 3 days afterward so that made it twice in one month which made me super super anxious about the whole thing. I did 2 pregnancy tests in January which were negative and 2 in February which were negative as well. I did get my periods for all three months but I was experiencing terrible pain and irregularity in my blood flow which led me to make an appointment at the doctor to do an ultrasound. Apparently nothing was seen on the ultrasound. So am I stressing for nothing or am I pregnant. According to google I could still be pregnant - I know it’s stupid to google such but I’m freaking out since this was the first time I had sex ever.