Useless

I miss being the father that i should be. I have to turn my son away sometimes as he often asks me to pick him up, carry him on my shoulders, run along with him. I am tired of giving him excuses like, "daddy cant do that" but why not daddy, " i am not well enough, or daddy has got a poorly head", to which the reply is Oh. Just looking at his little face breaks my heart as he is clearly thinking, but why not daddy. I even have to watch him cry his eyes out because i cant play with him like i should.
My wife takes him round to his nans house and he loves to play which i am grateful for but he thinks i can do the same at home. Its not just the physical element, its also the mental side of it. My wife does not like leaving me alone with him just in case i have a funny turn. I often forget to do certain things and she feels i am not capable of looking after him.
I also feel great sadness when he is invited to certain outings like the other day he was asked to go to the Monkey sanctuary with my wife's family, I could not go due to there being a lot of walking and looking up involved. Just the other day he was invited to his little friends birthday party at the snow dome. All the children had two hours on the snow play, where they could go on the sledges and play in the snow. All the mothers and fathers were there and all were very excited as were the children to get onto the snow. I just stood there and felt broken hearted as my son was led away with all the other parents to play on the snow. he just looked at me as to say, why aren,t you coming daddy. I had to sit in the cafe looking out the observation windows at him playing and he kept looking up at me with those sad eyes. I feel terrible . The last time we went running down the road together was last year pre op and that's when i collapsed in the road. I so wish i was my old self. I feel awful most of the time as i know my wife's family think i am just being lazy. Just today i dropped my wife and son at her mothers and her mother asked why i was not going out with them. My wife explained that we had gone shopping yesterday and that it took too much out of my and i was not feeling very well. I caught the look of my mothering law out of my peripheral vision, rolling her eyes and shaking her head in disapproval. I feel worthless as both a father and as a husband for not being able to do the things i should be able to do with my son and because of the things i forget to do when asked and for not finishing things i should have done by my wife. I sleep on the sofa for which i have done for the last two or more years because of my snoring and sleep apnea which keeps everyone awake. I have sexual problems because of my Syringomyelia so that makes my wife unhappy as she wants another child before she is too old. My wife is constantly shouting at me because of things i forget to do or because i cant do them and because i am not working and we are close to bankruptcy because of this wretched disorder. I keep thinking that maybe my son and my wife would be better off without me, and my wife has suggested me move out but because of financial difficulty i cant even do that.
I bet there are many other sufferers out there who are going through the same thing.