BFN and blood (tmi)

Rachel • I`m 20, living in Perth with my partner who`s 18. I have a beautiful 8 month old son named Jase.
Its been 17 days since I first had unprotected sex with my partner. I've did 3 tests and they all came up negative, but today while I was on the toilet I noticed something (TMI) a blood streaked bit of mucus. I have had sore breasts, and felt a bit off lately, but I'm also due for my period in 3 days! I'm nervous, and excited! I don't want to get my hopes up though! I'll do a test next week if my period doesn't come :) Would love to hear what anyone else's thoughts are, and nothing negative please :) TIA
UPDATE**
I went to the toilet again, and there's more!