Am in terrible pain, cant sit, or walk far, cant bend or lift , should i have a spinal fusion?

i have just had a ruptured disk and it is laying on a central nerve, happened over 6 months ago but i am stil in pain

Speak to your Doctor! If surgery is possible and needed he should refer you to an Orthopedic Surgeon. Find out from them what other treatments are available and what is likely to happen if the surgery isnt performed if it is needed! You need to know as much as possible about 'your' condition.
No-one unqualified even if they have had surgery themselves should advise you whether to have it or not! They DO Not know enough about YOU!

I say yes my cousin had it done and he feels great he is very happy he did it

It sounds the same as what I suffer from, SCIATICA. It is where the main Sciatica nerve is touching other nerves and sending pain down your leg. It is a nasty pain and all what you can really take for it is (Ibuprofen (Advil) and keep mobile.

This is something that needs to be discussed with your doctor. Get a second opinion if you feel you need one. But this is much too serious to listen to a bunch of people on the internet! Don't take this type of medical advice from anonymous strangers. That wouldn't be very wise, in my opinion. Talk it over with real doctors. Please!

I know it's not nice so close to Christmas, but I would like to advise you to visit a hospital until it is better. I think you would benefit from a little bit of treatment. I hope you recover soon.

Sounds like Sciatica. I had it and was on morphine but was still in a lot of pain. My doc refered me to the hospital and I had an MRI scan and then I had what they call a Root Nerve Injection.
So far so good, not 100% but getting there. Dont go for spinal surgery unless absolutly necessary.
You have my sympathy. The pain was sheer hell !!!!

If you know that you have a ruptured disc, the I must presume that you have already had medical advice.
Spinal fusion is an extremely extreme measure and would only be recommeded by any competent surgeon as an ultimate last possible option. If all that you have is a ruptured disc, then I very much doubt that a spinal fusion would be a necessary option for you.
Speak to your medical advisor, who may recommend surgery to remove the disc, and then again may not, depending on your personal medical situation.
Only a competent medical professional can advise you properly in this matter, but I will say that the removal of a spinal disc (Mellisectomy?) is not an unusual procedure and can produce good results. I stress the "can", it is not a guarantee, and I also stress that you should seek proper professional medical advice.

Sound like you need a good crap.