What do i do i need help?

ok i am a united states marine and i have a girlfriend that i have been dateing for 2 mounths now she lives 2 hours away i drive up and see her every week end i even took leave to go stay with her for a week every thing is going good but i have a felling that she is getting tired of me or maybe i dont know i mean we talk for hours every nite she call and wakes me up every morning i mean she is a great girlfriend i just dont know i get the felling that she is pushing herself away from me what should i do i do not want to loose her what do i do to make sure i keep her happy i mean she tells me she is happy but i just get this bad felling i tell her i love her which i do and she tells me she dose but i dont know i hope she dose so what do i do