Plz help me needing answers

So by this app supposed to be ovulating but I had sex he pulled out than after a minute or to puts it back in than I went to the bathroom didn't see anything after like 15 to 20 minutes later I took a shower got dressed and seen a spot of red blood So I put a pad on and later on in the day it started to get this looking brown want much so i didn't change it but can anyone tell me anything plz