Am i too heavy for my pony?

Ponies that size are deceptively strong. You shouldn't be riding him extensively, but getting on every once an a while would be fine. In my opinion, it is better to ride him a bit to keep him in shape than not and let him get fat and uncomfortable. If you are really looking for something to do with him, you could break him to drive or do natural horsemanship with him and have him be a "trick pony." As long as you are not riding too much and are not using him as your primary riding horse, you should be totally fine. Good luck and happy riding!