Red spotting only during sex?

TTC #1 and now on CD 27. Ever since about a week ago I've been having red spotting during sex. At first I thought it was an early period but the spotting only occurs during sex, and I have no cramps. Also usually premenstrual spotting is brown. I'm confused what this means. I really hope I'm pregnant, and I feel pregnant this month, but I don't know what this red spotting is. Could it just be some sort of abrasion or is it probably my period starting? Thanks!!!