Be sure to get plenty of sleep. Go out of your way to make sure you get to bed earlier than usual. Eat a healthy, balanced diet with plenty of fresh fruits and vegetables. Do what you can to decrease the stress in your life. Either eliminate it at its source, or have a good way to relieve it such as exercise. (Yes, an obvious one) Keep your anus clean. And you might want to try Tucks. I've never used them but my sister swore by them during her pregnancy and after giving birth.

Even though your culture came back negative, I would think there is no harm in applying an antifungal cream such as miconazole to your anus and urethra for a week or so anyway. Even better, apply a combination of miconazole and an antibacterial cream such as bacitracin. I was once prescribed this combination antifungal/antibacterial for urethral burning and it worked beautifully.

When I've feeling run down from stress I also take a multivitamin that has extra B complex, C, and zinc - a generic knock-off of Stress Tabs. They do seem to help me feel more energetic and get back to my normal self. (Multivitamins are a bad idea, though, if you have liver problems or drink a lot of alcohol.)

Oh, and last, get yourself a job that offers health insurance. Good luck!