My girlfriend lied and is cheating on me?

[helpmeplease]

Well my girlfriend and I were going to go to a movie but she cancelled on me and then she said she couldn't go. I later found out she went to a haunted house with one of her friends instead. So she ditched me. So instead of staying at home like a loser, my friend and I went to another girls house to watch movies. There were two girls there and 4 boys. And to clearaify things were all just friends hanging out having a good time.Its not like anything happened. Well she later text me that night and asked what i was doing and i told her i was at the girls house and she got really mad. she started posting multiple tweets on twitter like "**** you"," I thought things would be different with you #seriously #anygoodguysoutthere", "just not happy", and "pissed off, your an ***". I didnt respond to any of these tweets and i know for a fact there about me. Who elses whould they be about?!? this morning i told her i was sorry for whatever i did and asked her why she got so upset and she said she wasn't upset so i said "you seemed pretty upset by your twitter posts", then she replied back with "That doesn't mean there about you".so if there not about me who are they about?!? So shes either cheating on me by the statement "I thought things would be different, ANY GOOD GUYS OUT THERE" or she just lied to me by telling me their not about me cause obviously they are. I dont know what to do and i would like some opinions. THANKS

[?]

This girl is a phsyco bitch.Break up with her dude

[kate123]

ok, you can never understand girls, we are very unpredictable some of us don't wanna look helpless..
maybe your girl was just pissed, and remember we can always deny things.. ok don't be acting all crazy. btw girls has really high pride

[lola]

How can you bear that bitch?! Dump her! Unless, you love her a lot, if you do, go and sort it out but if she is still being bitchy DUMP HER! Tell everyone how small her vagina is!

[Ivy]

Sounds to me like your relationship problems go deeper than this one mishap. Maybe she's looking for a way out, and wants to make you look like the bad guy, or even make herself look bad so you'll dump her. The fact that she lied to you and went out with a friend instead is a big red flag. In a relationship, you should have enough honesty to just say 'Hey, I just want to hang out with my friend tonight'.
Bringing social media sites (IE Facebook, Twitter etc..) into your fight is a quick way to ruin a relationship. If you feel like your relationship is in trouble, pull her aside. Take a few hours to sit down alone with each other, no phones, no Twitter, and no outside opinions. You two really need to sit down and talk about your relationship. Lay all your cards on the table and figure out where you both stand.
For what it's worth, I don't think she's cheating on you.

[Laura Renee]

Of course they were about you. She was jealous that you were at another girl's house and she had a little temper tantrum.