jus need help

Bobbi • Ukulelelove
Okay 
So 
I literally have no one to talk to, it's hard to talk to a mom who looks at u differently because ur not really her daughter. 
So here it is 
I had sex for the first time not to long ago with my boyfriend who I have been with for 10 months now.
Everything's been great.
My mom tells me
"Once you do the deed, you can't stop"
I understand that now 
Well 
First 3 days into ovulation 
I started bleeding 
A brownish red color 
It wasn't spotting
Jus looked like old blood then it stopped 
I'm confused as of what's going on, I'm stressing out cause I don't want it to be something I'm not ready for. I'm 19 
I jus know I'm not ready.