Your future will never be a reflection of your past, let alone this idealized form of the past that never existed. We are all a little guilty of framing our past in either a rather rosy light or a rather negative light. It is the way the brain is designed to highlight key aspect and haze out the dullness.
Nevertheless the factors that existed in your past that you believe made things better will not be the same factors you will experience in the future. You will never have the same set of factors again. Not to say the future may not be awesome with some awesome factors, just that they will all be different. Age amongst them.
I think about the aspect of pain for example. That will never be what it was when I was younger. Pain has morphed in my life. It has grown into this living breathing beast. It has expanding into more than one pain condition. Hard not to idealize a time when there was just One pain condition, isn't there? I think to myself that I really coped well back then. But in truth I didn't. I fought hard to cope back then. Because pain is pain, no matter if it is one pain condition or three. Three sucks a lot, yes, but one sucks just as much. It was brutal and hard and I fought depression there for a bit. It was not a rosy happy story. But one thing is very true, I did cope well in the end. I reached a sort of plateau of coping really well. And then more pain came into the game. Sort of through me off my game, slowly, but surely.
And I will never return to the plateau of coping. I need to learn new ways to cope with new circumstances and factors. I am a different person with different levels of pain with a different life.
So yeah... accept the now. It is all we have. We need to move into a future that is unknown to us where we can accept all that we are really doing is improving on the person we are now. I have to accept any improvement on my circumstances Now is what I am aiming for into the future. Not to be what I was. What I was is not a comparison anymore.
Another example occurs to me. I think now that I am at the pain clinic that I have this desire, an earnest desire to work full time again. I think to myself... it must be better than it was before. I must be better enough that all that happened before would not happen again. You see, I have tried to dull what happened to me at work so I don't think about it. Dull it so that it is not as intense as it actually was. Makes me believe in some sense I could work full time again, even when others have told me I can't. I just think financially it makes sense. I suppose in every other way it does not. I project on my past self this sense I was strong, and I pushed through the pain and I persevered. That is true, but I was also in too much pain, I had no life because of it, and I was suicidal. I can't let myself forget the reality of what happened there.
I accept the now. If in the future I do vastly improve I will work part time. If the part time works exceptionally well. i will consider full time. That way I will not force myself into something I cannot do.