Everytime I brush my teeth this happens ? I dont know why? Please answer?

Everytime I brush my teeth reeeeeally har to the point i bleed I get like maybe like a sore thingy on my gum. I woke up and my gum was hurting really bad nd i got up to look at it. Idk why but everytime i brush my teeth I get a sore somewhere in my mouth. Its starting to bug me alot kus it hurts sometimes. Idk could I be allergic to the plastic in my tooth brush? Should I get a new toothbrush and see if its cause of that? This is the first time this happens when I got that tooth brush so idk. i got it maybe 3-4 months ago. or more idk ima get a new one but any answers?