I can certainly see why you're grieving. Those are a lot of losses in a relatively short time.
I understand the money situation. However, there are clinics who take people on a sliding scale--that is, based on how much they can pay. I think that would be something good to check out.
You haven't said anything about your being religious. If you feel comfortable about it, then you could meet with a pastor or priest or someone along this line.
I definitely think you need to talk to someone. As you say, your feelings are really beginning to affect your whole life, and not for the good.
I appreciate your sensitivity in not wanting to "use" your girlfriend, since you don't feel like you love her and probably aren't sure, then, of a long-term future together.
In the meantime, how about checking out the social groups we have here? There might be some with folks who are also grieving.....And you could meet other folks who will give you some other people to talk to and who can be a support to you.
I hope this information will help.