Can you recommend software to help me reduce my internet use?

I can't recommend anything in particular because it is so long since I used such a program.

There are programs out there though, so searching in Google or asking in health forums should turn something up quite easily. I know this because I used a program to remind me every so often to take a break, because my computer use was putting a strain on my hands, wrists and arms. 

This kind of software may help you, but don't expect it to work if you have a strong compulsion. In that case you may find yourself just bypassing the software when it asks you to stop. Some software may disable the computer and need you to wait before you can bypass it, but again you may find yourself doing this once the delay has passed. In that case you really need to seek help for what underlies your behaviour, and your doctor should be able to advise about that. This is the kind of thing that a therapist can help with, but your doctor can advise on what may be best for you.