can i be pregnant?

hi so.. i have irregular periods. i skipped a period this december,and according to this app i should get one around these days. frankly,i had unprotected sex 1.1., when the last day of ovulation supposedly was. about that sex i had,my bf was sick and peed before,i rode him for a minute,maybe two and pulled out and he was not close,he came like 10 mins after he pulled out. so i know the chances are low but however,i have really light bleeding for 4th day now,its not a period cause its really light,pinkish and im scared if it's implantation bleeding...i'm planning to take a teat tomorrow. anyone had this type of bleeding and what is it?