I was spinning when my friend hit me(not hard)on my backbone. it hurts when i press on it. i was wondering if it's fractured? or if i'm overreacting.

Well, I'm not sure: you're really overreacting, but maybe! Very likely this is just a bruise ... even if you can't see any discoloration. It takes A LOT of force to fracture the spine. You can put some ice on it for a few days but expect it be better very soon. Stay well:)

Not fratured: It takes major trauma to fracture a vertebra in your spine. Moreover it will hurt very badly and not allow you to move around. It seems your pain is more like a tenderness. I would not worry too much about it and carry on your normal activities(do not press on it since that seems to be when you hurt).