This happened to me, but it only took me a week to have problems.
When I had the MRI the surgeon told me that I had re-herniated the same disc even worse than before so I had to have a second microdiscectomy. That is what could have happened to you b/c my pain was so much more severe after the surgery, so if you weren't careful about bending/lifting/or even straining to go to the bathroom (which I did b/c the pain meds make you constipated) then you could have easily re-injured yourself. I know you are worrying, and it is very hard not to b/c I know I was having panic attacks, but the MRI is the best thing you can do right now to see what has happened and how bad it really is. You just need to make sure you communicate to your surgeon and let him know how painful everything is, but until then the only thing you can really do is try to stay somewhat positive (I know it is very hard) and do whatever you can to stay comfortable while you wait for the MRI results. Sorry this isn't a lot of help, but I hope you feel better soon!