I am the only female in my medical class. I don't want to have anything to do with the Kafirs but academically, I need to have friends to help me along the way. They see my hijjab as a problem and I don't know what to do.
You can find any position in Islam with respect to this, from the very conservative answer «A woman must not travel except with a mahram and a man must not enter upon her except if she has a mahram. So you cannot study in this place.» 1 over a moderate conservative «you can join mixed gatherings as long as all people respect the given rules of Islam»2 3 until a reform position «There is no interdiction of gender mixing in the quran. As long as you dress properly and do not seek a forbidden relationship, it is allowed» 4.
As the very conservative position is not an option for you anyway, you may opt for something close to the moderate position. You may study with a group of students who accept the rules you explain to them and whom you trust that they will do so, and you meet in a public place.
You co-students with whom you learn would be collegues rather than friends. As private friends, you can chose female friends you like.