I'm 15 and think I might be pregnant, please read! Do you think I'm pregnant?

This month I started taking birth control, I started taking it on the first day of my period for July (8th). I'm on the birth control Seasonique so I only have my period once every 3 months. I was taking the pill for 7 days straight (although on 2 of the days I took the pill 2 hours later than my usual time) and on the night of the 7th day (15th) I had without a condom with my boyfriend. Now every time we have we don't use a condom and he goes in me every time which is quite a lot.Today is now the 28th and I've been on the pill for 3 weeks and it's been almost 2 weeks since I started having without condoms. I'm experiencing things like bigger , lower backaches every now and then, dizzy when I stand up, and tired all the time. I know those could just be symptoms from the pill but 2 days ago when I went to the bathroom I had light pink blood in my underwear and when I wiped, I started to get a runny nose and a sore throat but now that went away, then that night I started to randomly puke. Last night after I ate I puked and today after I ate breakfast I puked again. Could these symptoms just be from the pill or because I'm actually sick with something or do you think I'm pregnant? Please let me know what you think ASAP. I'm 15 years old and super nervous, please don't lecture me because there's nothing I can do about it now. Thank you.