I'm sorry to hear that your mobility has become a 'bit of an issue', but it comes to the majority of us at some juncture in our lives. When it comes early, it's a real pig to come to terms with as you're discovering. However, don't give up hope - you will learn to deal with it.
I was always a bit of an action man - gymnastics, trampolining, parachuting, hang gliding, paragliding, martial arts and then twenty five years as a flying instructor before I was forced into early retirement with spinal problems after surgery.
I've been stuck in a wheelchair for about seven years now and I used a mobility scooter and sticks before that. Thankfully, I can still stand (with sticks) to swap seats etc. and use the loo, but that's about it. I can't walk anywhere - just one or two steps. As you can imagine, this cuts my options down a bit with regards carrying kit, but I always manage somehow - in fact only last weekend I shot a wedding for the first time in years and apparently I still haven't lost my touch.
I use an electric wheelchair - manual ones are fine if you're young or very fit, but no good for old farts like me. I wear a rucksack on my chest and hang various bags around the chair - I even manage a tripod occasionally. As well as lugging all that stuff I have to steer the chair and an Assistance Dog (who's a bloody marvel). Although I'm often tempted to throw the towel in, I'm a stubborn sod and just keep pushing.
Feel free to contact me if you want advice and although I don't use them myself, there is a
Disabled Photographer's Society.