WOW, pets have a thing about returning from Rainbow Bridge to let us know they're awaiting us there! That's why you need your laptop/tablet/phone whatever next to you, all the time. There are so many fun posts in the Off-Topic area that I know you'd enjoy... just leave a "like" on one or two that give you a smile, and we'll know you're around.
NEVER feel useless or you've overstayed your welcome on Earth, Moody. All this is for a reason: even if you never know what that reason is, entire medical books may very be written about your case and resilience someday. Whatever you're enduring now might lead to a cure to prevent countless others from enduring it. They may even name it Moodyosis or something...
Just know that we're always here, ready to share a smile, a bad joke, a digital hug or even email your kitties some treats. Keep in mind that Florence Nightingale was so convinced that she was dying that she spent over half her long life lying on her death bed - and dictated most of the book that became the first modern nursing manual. Even from her bed, she impacted billions of people and changed the course of medicine. Never dismiss who you are or the effect you have on others, friend.