I'm so sorry. Sunburn hurts. Neutrogena cold cream is the best. The main thing is to keep your skin hydrated with something soothing. The dryness is what causes the tight burning feeling. If you have tea bags make a strong pitcher of tea, bring to room temp or chill if you like and soak a cloth in it and keep it wet with tea on your skin or keep spraying your skin with it. I keep a prescription of Silverdene for sunburns. It stops the pain almost instantly and keeps the skin very moist. It will keep for years in the frigde. Next time you are at the Drs. ask for a prescription. Great for kitchen burns too.
If I were you I'd be calling mom or dad or some relative to send money for meds.