Help!

Quick question- so I've only been on Birth control for 3 weeks, and I've had unprotected sex 3 times ( 2 times
​He finished outside , and 1 time he finished inside) I have just randomly started bleeding , but I shouldn't get my period for another 2 months. I forgot to take my pill a couple times and I'm scared that maybe  something is wrong now. It's too heavy for spotting but too light to be my normal period... Does anyone know what's going on?