Can Mobic Taken For Shoulder Injury Cause Spotting And Severe Low Back Pain ?

Hi! I have been getting treated from my primary care for a shoulder injury. On Wed March 9th I went to the doctor and he prescribed mobic 15mg for my shoulder. I took the pill at 4pm and around 7pm I took a shower and when I cleaned myself, I noticed spotting of blood(thick spotting) I assumed it was from the end of my menstrual. I got my menstrual March 2 and usually only get it for 5 days and after the 5th day maybe it lingers a day or 2 like brown when I shower or wipe and then it's completely done, so I thought it might just be the end of my menstrual. That night, I was also suffering sever lower back pain and could not get up from bed and when i tried it was painful. I have a herniated disc so I just thought maybe the change of weather caused me to feel it more, but the feeling I had wed night wasn't my normal herniated disc pain, it was much worse and the vaginal bleeding continues. It's now Sat and I am still bleeding like I have my period and my back is still in pain and I feel a little cramping like period cramps. I stopped taking my shoulder medicine thinking it could be giving me these symptoms as a side effect, so today I stopped. I went to the urgent care center Friday for all this. They did a urine sample and x-ray on my back. The dr. said everything looks good. The dr. told me if the bleeding doesn't stop by Mon, I may want to follow up with a Gynecologist. I'm worried there could be something wrong. I shouldn't have my period for 14 days and the lower back pain doesn't feel like the norm I usually have.

Is it possible, those pills could be giving me these symptoms as a side effect. The Urgent care said my urine looked fine, but I don't understand why I'm still bleeding. What do you suggest?

Thank you!
Michelle