HELP. Possible pregnancy

Hi I'm 16 , & I'm sexually active with my boyfriend. I've been late on my period plenty of times. We don't use condoms I'm allergic. I'm 4 days late. We had sex about 4 times, 3 times it ended in oral sex and one it ended he came on my stomach right as he pulled out. I've had a uti a few weeks ago . Today I've been noticing everytime I go to the bathroom and wipe there is some light blood. I have cramps . Advice? Please help