Cramping and back pain?

I was in the shower, and my lower back started to hurt a little out of no where. I get back pain every now and again so I just continued my shower. Well all of a sudden I got some very strong cramps and my back pain got really intense. It was so bad it forced me to my knees while I was showering, and I felt something leak out of me. I’m pretty sure I just pushed a little pee out of me while I was down there but I was in so much pain I’m not sure. I’m 33 weeks 3 days, and this is my first pregnancy. Just wondering if this is normal, and if anyone else has had this. Thanks ladies!