Back Pain

Hello! I am new to this forum and wanted to get your opinions as to what might be going on with me. I have been having low back pain, more on right side,pain on both sides of abdomen,-worse on right, sciatica, pain down leg(thigh-inner anterior) and down to calf and also numbness and tingling. This has been going on for about a month and I think I strained my back at the gym doing lunges or seated leg press. I am having a really hard time sleeping-i can only lay on my left side with a pillow between my legs and then a pillow on the right side to support it. If I lay flat on my back or on my stomach, it is most painful. Also, sitting is painful.
I work as a travel nurse and just started a 13 week contract. I seem to be better just walking and in an upright position. If I could just sleep standing up!
i went to my neurologist and he ordered lumbar spine x-rays (flex and ext) and also mri of lumbar spine to evaluate l5-s1. I have been on one medrol pack which helped the pain a lot-although I felt weird with the side effects. I am taking flexaril and some vicodin-this is not doing wonders for my stomach. He also prescribed mobic-anti-inflammatory and I have not started that yet, but will.
I just hope whatever this is, it can just get better because it is taking a toll on me and my family. I have to work-which does actually take my mind off the pain, but after 12 hours-i am in pretty bad pain. I have been doing my shifts every other day or two days so I can recover in between. I am worried to lift patients-although I have to do some and am trying to be very careful holding in my stomach.
I went to my ob and everything was fine with my reproductive system-had a ultrasound and it showed nothing. She then said she thought it was my back and that it could radiate to the sides of abdomen.
Has anyone had anything like this? I guess I will know more on monday for the results of the scans. Any suggestions or opinions would be appreciated.

Thank you
paige