I Need Some Advice

Okay well i'm 20 years old and I had unprotected sex with my b/f a week ago (5/8) on my period. Well the past week, I have been feeling really different. I know it might be too soon to say i'm pregnant or not but here or some symptoms I have been having. Well this week I have been really really tired. I have been going to bed earlier than I usually do and sleeping very good. I wake up being soar because I guess I have been sleeping so good. Anyway the past week (i know this is kinda gross) I have been feeling very bloated like my stomach has been bubbly (but I don't have to go to the bathroom or anything) I has been happeneing every day since late in the week from the moment I wake up to when I go to bed. I also have been kinda crampy. The really weird thing is that I also have been kinda depressed. I started crying one day this week for no reason. Also I dranked a few beers friday night, but the really weird thing is that everytime I drink i'm usually happy and stuff like that, but when I drank a little bit friday not. I started crying and fussing at everyone for no reason. I just been being by myself lately and being depressed. I know it's too soon to take a pregnancy test but I was wondering has any other people ever had these feelings before they found out that they were pregnant. Thanks!

P.S.

Yea I also have been having bad pack pain in my lower back (and I know it's not pms b/c I just finished my period). It's like I can't stand for a while b/c my lower back starts hurting really bad. I also picked up my 2 year old nephew yesterday and something felt like it was pulling inside below my belly button. I know it's weird but I don't know what it could be. I also have been having headaches. Do you think i'm pregnant or do u think these are signs, thanks!