I think you should first contact your doctor and explain to him about the cramping. Then, he or she will be able to advice you on the best way to relieve the cramping or if you need a thorough check up.
Yes u should head to the hospital immediately since yesterday. u could most likely be going to have the baby. my wife was leaking fluid with our first and the old woman next door after i told her told me to get her there that she was gonna have the baby. after induction of labor they did and 30 hours later i received a daughter. of course that was 1988. lol but it is like yesterday to me
Ring the hospital & see what they say. Being 3hrs from the hospital isn't ideal. If I were you I'd pack a bag & stay in a hotel closer to the hospital, if that's a possibility. You could go from mild cramps to full blown labour quickly. Good luck to you & congratulations :)