Could i be pregnant?

Okay well heres the thing...
Me and my boyfriend have been together for like 2 years and we plan on having kids... but not anytime soon!!!
I was supposed to start 4 days ago and theres hardly any signs of me feeling like I am going to start... my left...

boob hurts and that is it.
I have had these scares before but never got pregnant... but then again there was one time where I didn't start for about 4 months and then all of a sudden one night I was standing and I starting bleeding bad... like blood clots and everything... so I think I had a miscarriage but I could never really know. That was about 4 months ago.

I am so scared I am only 18 years old about to be 19 and I am too young to have a baby!!!
what should I do?
My boyfriend doesn't want this either right now, and I wouldn't ever get a miscarriage.

u cant get a miscarriage.
a miscarriage is when your baby naturally dies in your stomach
you can have one but I think you mean an abortion.

but anywayss
go to the guynocologist
talk to her/him and tell them
your problem

Its only been 4 days, probably too early to tell. But you should go visit your doctor and get tested.

1.) get a test
2.)use a condom