My cycle was almost a week late when I came on my first day looked normal but started to fade away later that night second day it went away then day 3 an 4 was light it turned pink and brown... my partner and I had intercourse before I came on my cycle could I be pregnant?

Possibly, but it may just be an off cycle. See what happens when you would expect your next period. If you can't stand the wait, you could try a pregnancy test before that time.