My girlfriend is in Prison

so, my girlfriend is in prison. i’ve never been in a relationship where i had to be away from someone for so long. she doesn’t get out until next june. ( she didn’t do anything serious ). i’m not even sure if i’m allowed to ask for advice. but has anyone been in the same boat? or a long distance relationship in general. the prison is about 6 hours away from me. please give me some advice!!