Kinda TMI

Amanda • I`m 28 years old. Married since 2011. We have a 5 year old son. Baby #2 due in nov2016!
So AF was due today, I always start in the morning, there was no sign of her. SO and I just had sex and now I'm bleeding. Sometimes I spot after we have sex but this it more than spotting. But it doesn't look like menstrual blood, it's super bright red. Any ideas?