I Had Unprotected Sex With My Boyfriend On Oct. 23rd

I had unprotected sex with my boyfriend on Oct. 23rd and he ejaculated in me. The next morning when I woke up, I experienced watered down blood in my shorts. This lasted for 4 days, I thought it was my period (even though if this was my period, it was 7 days early) so I didn't think I could be pregnant. However, a few days after the diluted blood stopped I started experiencing mild cramps, I was tired all the time and eating like crazy! I thought I was just experiencing PMS really early (even though that has never happened). Going to work I started feeling light headed and had some nausea, eventually that went away. Fast forward to Nov. 24th (exactly one month from when the diluted blood started) I got no period. That's when the backaches started, and my headaches, post-nasal drip, I'm starting to get angry and sad very easily, gurgling in my stomach after every meal, sometimes a burning sensation in my stomach too, and my right boob was in pain for a couple days. I'm now 11 days late and I just feel terrible overall. I don't want to believe that I'm pregnant, but as the days go by I think more and more that I am. Was that watery bleeding last month my period or something else? Could I be pregnant?