Flexeril and suicidal thoughts

I was prescribed Flexeril (non-branded) 10MG for two weeks for back pain. I was prescribed to take 1 tablet at night before bed so I wouldn't be drowsy for school. I noticed after a couple days of taking it (I began taking it after having the injury for several weeks and seeing no improvement) that my back pain was in fact decreasing. However, I also began to notice that I had nightmares or intense dreams at night and that during the day I was somewhat "out of it." In the middle of the second week I definitely was not feeling myself and started having suicidal thoughts and was very irritable. I stopped taking it because that's not like me. The back pain was overwhelming...but the side effects were almost as bad.