I went back to the gym on Wednesday after staying away for a year and I think I over did my abs, My muscle are in pain, today is Saturday and I am still sore but I want to go back any way.
It could be because of the long break, but I'd recommend waiting a bit and if the same thing happens at your next gym visit contacting your doctor.
The pain you are experiencing is commonly referred to as D.O.M.S (Delayed Onset Muscle Soreness), and usually means the tearing of that muscle has occured, and it is getting stronger.. very normal though