Weird bleeding

Since the 14th of February i've been having really weird bleeding. It's not enough for me to say it's a period as it's also not consistent I just randomly start bleeding for like half hour in little intervals or straight after having an orgasm. However it's quite heavy if its spotting.

Today I started again at about 5pm, I felt it go onto my pad, but it wasn't heavy. I used the loo at 5:45pm, however when I wiped I had this weird looking stuff on the tissue. I've had clots

nothing like this it was squishy as I felt it "pop" when I folded the tissue to wipe again and there was no blood or anything on the second wipe.

I should add that I've been having major symptoms of pregnancy including my nausea, sore boobs. However these last 2 days I've had immense stomach, back, chest and vaginally pain. I should also say that I had the injection last month, but not during the "safe zone", but we never used any extra protection for the first week.