It turned up in the middle of sex, so I initially thought it might just have been too rough/hitting my cervix a lot (my (cis) bf is... sizeable and it's not always perfectly comfortable). We don't use condoms regularly (only if he wants to finish in me, I know pulling out is't a 100% method but I'm on the pill, so) but we were both each other's firsts and are/always have been monogamous, so I'm reasonably certain it can't be any kind of STI causing it. GP appointments are 2-3 week waits where I live and also have been closed a lot of the time for new year's/christmas so going to see them hasn't been practical.
The only thing I can think is that I'm on a new brand of pills, but this is three months into taking it and I've had no issues before. I'm sick of being on my period (bf and I are long distance but he's been home for Christmas and I really just want to have sex with him) and anxious in general. The 'fresh' bleeding seems to coincide a bit with when I'm turned on, e.g. if we've been fooling around a bit - no penetration though so again I don't think it's an infection.