What is going on??

For over a month I have been experiencing cramps in my lower left side that extend through my hips and thighs that feels like period cramps, lower back pain that makes me nauseous. First I thought maybe pregnancy due to nausea. That was a no. Then we thought maybe a kidney infection or uti. I had my urine checked and nothing came back as either one of those. No sign of infection. Next I thought maybe severe constipation. I have taken several things that aided in going to the restroom but still in pain. What could this be? Any ideas? I will probably make a new dr appt just wanted to hear others ideas.