Is it normal to be sore three days after a workout?

I added a new type of exercise to my regular workout and have had to stop for three days! It’s this thing where you lay on your back with arms and legs straight out and then lift arms and legs all the way up together. Also, I added five pound weights for my arms. I’ve been sore after workouts before, but nothing like this. Every time I move my ab section aches. Should I just keep doing crunches and discontinue this exercise?