Odd discharge?

Ok Im asking this because I am scared shitless of doctors. I just finished my period this week on tuesday. I was ually active with my boyfriend on Sunday and nothing happend. Then we did it again on Wednsday and when I looked down there was a big brown stain on my sheets, we did it 2 times yesterday and it happend again and not only that but it smells reallly weird. Now even if I wash down there I can feel it discharging from time to time and for some reason smells strong sometimes. Any help please??