What should I do about my girlfriend acting this way?

Hi, I'm dating this girl, we've been together for the past 4 months. We met at college. We had 2 classes together. We started talking and one thing lead to the other, we started dating. We had been together only a month, when i decided to take a trip to Mexico for a month. While there, I thought about her constantly. I tried keeping in touch, but she seemed rather busy. So, around my second week I decided I would just live up my time there and that's what I did. When i got back, we started talking again, and thing were wonderful. We went on dates we hung out a lot and all that good stuff. A little background on her, Shes head of a land management project, she's older by 2 years, she drives a sweet ride, she has 2 degrees and she comes from money; her family is wealthy. As for myself: i'm broke, my parents don't really have much money, i'm jobless still havent completed my 1 degree. Now, where i need advice is on 2 things. . . 1st, on my trip to Mexico, I spent ALL my savings. Everything I had, i spent. I don't regret it, but now i just don't know what to do, because i don't have a job. I'm going to college and i sometimes don't even have money for the bus much less for gas. When we go out, she pays but she also picks me up and drops me off when we're done. She tell me not to worry about it, but i do. What can i do to take that off my mind? 2nd, I think she's hiding me. I went out the other night with her and a friend of hers and her friend seemed rather surprised when i whispered in her ear and then she said something about her friend along the lines of "I think she's on to us". It seems like no one knows about me, not her family, not her sister, not even her best friend. They know i exist, but that basically it. They don't know we're dating, nothing! I've tried talking to her about it, but she get really upset and aggressive when I do. She tells me that she'll do it when she's ready and that i shouldn't pressure her. The other reason i think she's hiding me, is because when we are in the parking lot at school in her vehicle, And i try to kiss her, she stops me and tells me "no, I'm not into PDA". but when i tell her that no one is around and the coast is clear, she has no problem doing it. Am i just insecure and paranoid, or do i have reason?

hmm seems you're two worlds apart and coming from a wealthy family your girlfriend must be under a lot of pressure from family and friends to meet great expectations as far as her choice of partner is concerned so that should explain her strange behaviour. Yes she's hiding you but it's more to do with stalling for time and not necessarily embarrassment.you should realize that the moment she introduces you and her family or friends disapprove your relationship that could possibly be the end of it as is in most cases so your girlfriend seems to be dragging on because she doesn't want to lose what you have. The inevitable will happen obviously but relationships are about communicating our feelings to each other so tell her straight-up that you think she's hiding you and if she can't introduce you,you can't be her companion in the shadows. Love is amazing and openness is one thing common to it-if you love someone you'll want the whole world to know.