Unfortunately I don't know you very well as I'm new(ish) to PC but from what others have said it seems to me like therapy is important for helping keep you on track in the times when you are not doing as well as you are doing now... and sadly we all know those times will come whether we want them to or not.
I've found (and this is just me, it may or may not apply to you) that therapy hasbeen reallly useful in identifying bad thought patterns and finding ways to fix them so to help me feel better because sometimes better thought = better feelings. At least for me anyway.
I wish you well!