I assume both of you are still young. From her actions, I think you're still in the courtship stage, she doesn't seems like wanna commit a relationship with you for now.

There are times 'less is more'. To win her heart back, first you have to get a better control of your emotions and yourself. Your insecurities, jealousy and desperation are spilling all over, and these are the main reasons that she insist of not seeing you.

Think about it. When people coupled, it because they're happy and enjoy to be with each other. What have you done recently? Have you gives her enough trusts? Let her feel cheerful & comfortable to be around you?

or

You're just limiting her, telling her 'this don't do that don't go' to prevent her from leaving you?
There is no quick fix right now. Sending flowers won't help either, because she already feel annoyed with you. Letting her know this gifts are from you would only triggers those annoying thoughts about you.

Listen to your friends, let this be a cooling period.
Given that you've stalked her, and know her every moves and persons she meets. What could you do after this? Confront her? Ask her this and that? Tell her to tell the truth?

Do you know what are these leading into? These are leading you into a dead end. Not to say she'll leaves you, you will end up as a freak too.
She is not the only girl you'll ever meet. Same goes for her. It's a big world out there.

The reason that those advices is to give you some self worth and dignity. Have some respects for yourself. Let her know that you're strong, fine and able to get other girls if she decides not to be with you.
I was once like you too when I was young. Inexperience and naive. 

Just take some time off. Breath some fresh air.

After like 2 weeks time, send her a weird/funny joke. See how things go from there.

i was dating wif a gal that has been developing well for around 2 months+ dy...

until recently she keep mention to me that she's going out to hav a drink wif her frens... (mostly is guy) and those guys are known to hav feel to her... actually im ok with whoever she wanted to go out with... but everytime she'll go till very late and she need to wake up early in the morning (6.30a.m) to get prepare... when she's with her fren she dont like me to bother her! eg; sms or calls...

things continue to happen until 1 day i cant stand of it and im telling her that i am abit angry while we're on the fone...

the next day she's telling me that she was in bad mood and asking me not to bother her ! ok... then things became worst as she's starting to feel feedup by ignoring my calls and sms !!! i told her we need a talk ... she was not willing to do it and instead telling my frens that she NEEDS TIME to calm down.

at first i thought nth serious as she told my fren she wanted some time,space, and privacy... she felt that i locked her too much   i cant get any chance to talk to her now ... i've try to send her msg... but she get annoyed and telling me not to msg her anymore during this period ... she told me that she juz need some time... what is that??? what's the meaning of this ? should i wait ?
im feeling depressing now... what can i do to win her heart back ?

i was dating wif a gal that has been developing well for around 2 months+ dy...

until recently she keep mention to me that she's going out to hav a drink wif her frens... (mostly is guy) and those guys are known to hav feel to her... actually im ok with whoever she wanted to go out with... but everytime she'll go till very late and she need to wake up early in the morning (6.30a.m) to get prepare... when she's with her fren she dont like me to bother her! eg; sms or calls...

things continue to happen until 1 day i cant stand of it and im telling her that i am abit angry while we're on the fone...

the next day she's telling me that she was in bad mood and asking me not to bother her ! ok... then things became worst as she's starting to feel feedup by ignoring my calls and sms !!! i told her we need a talk ... she was not willing to do it and instead telling my frens that she NEEDS TIME to calm down.

at first i thought nth serious as she told my fren she wanted some time,space, and privacy... she felt that i locked her too much   i cant get any chance to talk to her now ... i've try to send her msg... but she get annoyed and telling me not to msg her anymore during this period ... she told me that she juz need some time... what is that??? what's the meaning of this ? should i wait ?
im feeling depressing now... what can i do to win her heart back ?

Man, just give her time to be alone. She needs it. She is just angry with you. That's all.

If she loves you, she will texts/calls you back after that.