should i be worried...? 😳

Autumn
Hey girls, I'm just a little worried and confused about what's happening.😖 please read and give me ur opinion🙏
So, my last period started on 7th Sep. I had protected sex with my boyfriend yesterday (25th), but before we got the condom on we were both so in the mood that he ended up putting it in for a second, and then he pulled it out quickly. 
(Maybe TMI) there was a tiny tiny bit of blood on the condom when we checked afterwards, but there was nothing when I went to the bathroom to check. But, around when I got home yesterday, I suddenly had some blood when I went to the toilet (red). So, freaked out a little and started googling but decided that it was probably because I was trying really really hard to stay quiet so maybe i clenched so much the friction caused some tears??
There wasn't any blood the next time I went to the bathroom, and nothing this morning either. But around noon today, there was suddenly blood again. I went to work for 7 hours, and after that I checked again and there was still some blood. I only really see it when I wipe, but (TMI) it's quite red and sometimes a little bit dark (like clots). Should I visit a doctor?
I'm thinking maybe my period's starting early? (the app says it should start a week and a half from now though). Will sex make it come earlier?
But I don't think it could be a STI? My boyfriend and I are each other's firsts and only.
Thanks for reading even though it's so long! Please give me your opinion! 🙏