I'm so sorry about your cycling events & injuries and I wish you a very speedy recovery. You sound like you really like cycling and I completely encourage you to keep cycling. Right now it might seems like the powers are against you cycling, but what you've experienced is fairly common. Don't feel alone. I had a mountain type bike years ago with clipless pedals and as I practiced on a quiet street and was really doing well, I was at a stop and basically just tipped over! I wasn't even moving. It happens.
I'm not sure of your prior experience, your bike set up, type of riding, etc., however I'm wondering if you would consider riding with platform or non-clip pedals for awhile? It would not be an indication of failure, but would allow you to ride and enjoy yourself without having to worry about the clip in/out issues. I think if you continued to have a lot of mishaps you might just walk away all together. There are some cool looking pedals that aren't platforms per se, but not clipless either.

Don't let this cause you to choose to walk away. Remember...if you quit cycling it's your *choice*. You can choose to stay or to go. I suggest that you try to keep things in perspective. I mean, in the long term scheme of things, this event might have some lessons in it that will be useful in the future.

Hang in there. You're strong and capable.