Try to hold off on the crunches right now. If you have bulging discs, the repeated flexion of your back will just push them out further. I would try some cobra stretches (lay on your stomach and prop up on your forearms or hands keeping your hips on the floor). The extension will help push the discs back into place again. You may also want to try some hanging spinal decompression from a pull up bar. Just hang from the bar as if you are going to do a pullup, tighten your glutes and lower back for 5 sec, then relax. you will actually feel your spine decompress- great to do if you following a training session. As for crunches, hold off, do planks but definitely no need for 500 crunches a day. Good luck
Nick Parmigiano MSPT, CPT