My professional advice comes in 2 parts
1) Relax. It is probably nothing to worry about. You have simply jumped back in to exercising these muscles too hard too soon. Reduce the number you do to about 10 - 20 and build up to 50+ over a number of weeks and you will find the cramps won't hit. Also, keep breathing, slow and steady breaths. If you hold you breath you starve the muscles of oxygen and they will cramp!
2) As with all muscles the abs need a rest. All exercise guidelines recommend that you work a muscle every OTHER day as they need a day of rest to repair the deliberate damage a work out causes. By working them every day you deprive your body of the chance to reap the full benefit of the work you did. That is why good workouts tell you to do mostly cardio one day, alternating with mostly resistance the next.
I hope this helps, Stef