I had sex with My Guy friend an we used a condom the following week I got my period as scheduled, then the week after that My boyfriend an I got back together we had sex all week an did not.use a condom now a month later I have a missed period an took a test an I'm pregnant should I be worried about who is the dad?

Yes... you will have to have a DNA test done. Because medical science can only guess within a one month long window.

And you CAN get pregnant while using a condom. They are 80% effective, there is no 100% effective birth control.

Yea but I caught my period as scheduled now if I diddint catch my period then I should be worried don't u think