D3100 no longer working in continuous mode?

I've had my Nikon D3100 for over a year now. It's taken thousands of photos. It used to take 100+ at a time like i needed since i have a wired remote and can't keep running back and forth to the camera. I recently realized with and without the remote continuous mode is hardly working now. It will take a few shots. Then quit.take one or two more. Then stop again.i've reset my shooting options and everything. My manual didn't help at all.help please?

Added (1). Of course i always reformat my cards after everything downloaded to my computer. I reformat them with the camera. I had no idea it could be my cards though.i've never had this problem before

When was the last time you formatted your cards?

At the end of each shooting day, after copying all your images to your computer are you formatting your card using the format feature on the camera?

This must be done routinely

Do all your memory cards act the same way?