A counsellor sounds good.
It might not be you you know, be prepared for that. People's lives are all squished everywhichway, some of my not so convenient friends have fallen by the wayside, not because I don't like them, but because it's so hard to make time for all, I think to some extent it's natural wasteage. There's no ill feelings.
I guess it's tougher when you're single and most people you know are married. I am SO guilty of seeing my friends far more when DH is away than when he's here... I'm not using my friends, I simply have more time when he's away.
Your limitations with your health could be another limitation to friendship, or rather, the way you explain/excuse yourself could be "Can you drive, I'm decorating and my arthritis is playing up" does sound a contradiction in terms... people don't automatically know how your arthritis affects you, so it would be better to say "I've over done it, got a flare up".
You probably ARE a nice person, perhaps you DO have some responsibilty in your friendship failure (I know I certainly have in the past). Counselling sounds an excellent way to explore the bits you can control, where YOU may be going wrong, where you're not and how to change what you can change.
I wish you the best of luck. There's too many lonely people in the world, and not enough time to make time for many people too.
Try not to kick yourself. Whatever happens, whatever 'responsibilities' you may find regarding your own behaviour, assumptions, worries, it is safe to say it's not ALL your fault. I hope you find a few friends who understand and will stick by you even if you are a pain in the ass... I'm a massive pain in the ass, a true friend will tell you when you're being one and still love you... to a point
Sorry for the long winded response. I was so lonely once upon a time. There can be a happy 'beginning' for you.