It can be difficult to admit you need help. Not only are you willing to admit that you have a problem with lying but you’re open and anxiously attempting to find help for it. I find this to be very positive and encouraging.
You say that you engage in telling “white lies.” I know for some people there’s a distinction between “white” and presumably “regular” lies but in reality there is no difference. A lie is a lie. A lie is the telling of an untrue statement that you know not to be true but act as though it is. As you have experienced telling one lie typically leads to another and before you know it, you’re entangled in a web of deception with no easy escape. That seems to be the situation you’ve found yourself in.
People lie for multiple reasons, mainly to make themselves look better or to avoid punishment. I don’t specifically know why you lied or even what you lied about. What I do know, based on your letter, is you’ve apparently been caught lying. It is negatively affecting your life and relationships and you need help to change.
You’re residing at a university in Texas. Most universities have very good counseling centers that are free of charge and open to students. Call the university counseling center and make an appointment with a therapist. I don’t think you need a special type of therapist for this issue because to the best of my knowledge there are no therapists who specialize in the behavior of lying. I think this problem can be properly addressed by a qualified and competent counselor. If the university counseling center is not an option then you may want to try a counselor through your insurance company. If none of those are options for you, you could locate your local community mental health center.
As I mentioned above, I am encouraged by your willingness to seek help. It shows that you’re motivated to change. This greatly improves your chances of being successful in changing your behavior. You’re also lucky because you have a girlfriend who is giving you a second chance. Good luck and I hope you will keep me posted on your progress.