Why is my girlfriend acting emotionless?

ok this is how it goes ...
we've been going out for about 5 months, and she recently changed her attitude towards me. She seems not to care about anything much and stays most of the time home. She does not approove any interest into our relationship anymore and preferes to do nothing than to hang out.
Now, few days a go, I bought her a gift and she just took a 2 seconds look at it, said it's cute and gave me an emotionless kiss ... she wasn't like that before.
That's just an example of what's happenning. This sh*t is beginning to bother me because I don't really know what's happening to her ... I know her friends well and she doesn't seem to be interested in somebody else cause she's on AOL most of the time ...
Does anybody have any ideas about what might be going on ?
thank you

There does sound like something seems to be bothering her ... Have you tried talking to her about it. Telling her how you feel and what she's doing to your relationship. Maybe it's something that's happened and she doesn't really want to talk about it. Get her to open up a bit more showing her you care a lot for her. If that's not the case then give her time alone.. time apart from you might snap her out of what she's going through.

Good Luck! Love to hear how things go..

I've talked to her about it several times and she still doesn't care much ... all she says is '' I'll try to correct myself ''. I've told her about my feelings and offered her my aid if there is anything she is worried about. She never wants to talk about anything ''that'' personal.
Also, what bothers me a lot, is that she is always laughing with her friends (both girls and guys) and when she comes to me she becomes nearly emotionless ...
I really love her and want to sort things out but she's not giving me any info and I'm completely lost and feeling rejected.

Communications is your key to this situation. You must take the time and be very understanding because there is somthing wrong here.. could be a form of depression many things can trigger it.... family member sick, a personal fear about something, afraid of becoming too close or not ready for a real realtionship.... you sound like a keeper being so sensitive and buying her cute little gifts awwwww......its her not you but the only way to find out is to get her to open up to you...tell her how you care and it would mean a lot if you both could talk so you understand why the big change....just be very reissuring that what every it is you would like her to share it with you....if she could open up to you it would mean a lot to have a deeper relationship by helping each other ....let her just know you are here for her and she should know that. Thats all you can do.... its a test of your patience and understanding as well... good luck hope it goes well!!

Talk to the girl. She may want to break up with you. She may be sad over something. Asking strangers on the internet what is bothering her isn't going to give you this answer on this one.

Teens are notorious for not speaking their mind if/when they want to break up with someone. They just act like stick in the mud drag until the other gets the point. But don't go on assumptions. Talk to her.

I do talk to her. Always. About feelings and family stuff. And yes I agree that Internet is not the best place to talk about my problems... but since I can do absolutely nothing, I turn over to people who have already experienced similar situations.
the problem is that she will definately not talk ... I've tried so many times I don't know what to do now.

Cut it off man, five months is a drip in the bucket. I also agree with her wanting to break up with you and not just, TELLING YOU. Chicks can be so difficult.

She dosent want to breakup wid u, but what I ud suggest is you break up with her and see how she takes it. she has started to take you for granted this is something that all pampered gals do. You need to take it step by step

Here is the sure shot solution for your problem and it will for no matter what:

Text her your situation and be sure tha she knows what you going through. Then also text her that if you are gone you will be gone for ever. But she will still not react to it. Dont panic ..
Next day I mean after tellin all this tha you will be gone for ever is she behaves the same ask her out or do something to test her emotions towards you.. And this time too if you get disappointed BREAK UP..
Now leave it like that for the day may be she will try callin you back or not. If she never calls you back THis RELATIONSHIP had nothing left in it dude so carry on wid your life. BUT if She does call you back again and again.. don pick the phone yet or just tell her don call you. But after some hours call her back and ask her if she can see you now or talk to you. Go and sort everything out then. She will surely listen to you. THis is the only way to mend someone who takes you for granted.

dude im in the same situation right now been with her about 5 months and everything you say is what she is doin..is so annoying she used to be really close hug me kiss me tell me she loves me but now shes like not the same person and when her familes around her shes fine haves a laugh and same with her friends...wud love to no what to do.