Could My Late Period, Cramps, And Back Pain Be Due To Pregnancy Or Other Factors Like Irregular Cycles, Iron Deficiency?

Hi I had sex 16 days ago. My period was supposed to come 2 days ago but hasn’t. He didn’t cum inside me. He pulled out. I have irregular periods. I’m 16. My last period was 37 days ago. It came one day late. I do have iron deffiecny and iron problems m. I’m a little bit week. I stopped excercising about 1.5 weeks ago. I don’t know if I’m pregnant or if it’s not coming because of my body. I have cramps and back pain above my belly button