Light bleeding and slight cramps, I have pain while I urinate

Hi. I got my period on March 6-13 and we had withdrawal unprotected sex with my bf on the next day March 14th. And we had withdrawal unprotected sex again on the 21th March. And on April 17th we had another withdrawal sex. My menstruation cycle is irregular so I was expecting to have my period on the 28 - 35 days and April 24th today I still don't have. However, we had unprotected sex with my bf again today April 24 and he cum inside me. During our intercourse, I felt uneasy and hurt so I ask him after he cum, if I bleed and he said yes. After 30 minutes the bleeding stop though but then after 3 hours when I peed I bleed lightly again but it doesn't hurt anymore and after 11 hours, I peed again, I noticed an apple red blood(very red like the 1st day of your period) discharge in my vagina. I was hoping its my period starting but is it possible to have your period even after unprotected intercourse? (I'm having a slight cramps) or should I be more concern about this? (FYI: I used the test on April 17th but its negative. When I noticed the unease pain, I tried home remedies for treating diseases can I still get the infection?)