First off, don't even consider going back to school until you get your depression under control. If you do, you will seriously shoot yourself in the foot. If you need to, take a semester off while you work on this. This will also give you some time to boost your ECs, like volunteering or shadowing.
Secondly, you have two years left before you graduate. Get good grades from here on out. You should probably not apply to med school until your Sr year considering the bad semester you just had. You need that extra years worth of good grades. This means you will have a year off between graduating and matriculating, but it's better than trying to rush things and screwing everything up.