Pregnancy :: Unprotected Sex, Could I Be Pregnant?

I'm 18 years old and have been on the POP pill since I turned 14 due to discharge problems. June 2013 I went onto the depo shot instead of the pill. I came off any contraception December 2013 as I was not sexually active. Recently, I have been having unprotected sex (past 2 or 3 weeks). I also had unprotected sex during what I thought was my period, though I then read online it may not have been a period, and just spotting. Since first becoming sexually active again, my discharge has become a lot heavier and quite watery. Sometimes it smells, but not fishy. 

It sounds stupid, though I didn't think I was ovulating again due to not having any periods for so long. 

A couple of questions;

Can you get pregnant on your "period"?

should I take a test? 

Are these signs of pregnancy? 

How early can I take a test? 

Am I more likely to get pregnant due to not knowing when I ovulated? 

Any other points you can add would be taken into account generously.