The fact that you managed to turn your life around before, means that you can probably do it again.
Remember when you were 'motivated and full of energy'?
Remember when you were proud to have 'accomplished a lot'?
You don't say what it is that has caused your downward spiral.... except for the fact that the 'past couple of years have just sucked the life right out' of you... Is it time to change your job again maybe?...
Having sleep problems will result in a lack of energy, so that part's not a puzzle.
To create energy, you need to use energy... so get out and about. The more you DO, the more you will want to do, even if you just start by going out for a walk. Then maybe you will want to go for a jog or take up some sport. It's the opposite of the notion that too much sleep makes you more sleepy.
What has happened to cause you to feel uncomfortable with people? You say you used to be confident, popular and respected.... find that person deep inside yourself again. He must still be in there somewhere... Bring him out. Let people see him.
The suicidal thoughts need to be addressed by a professional probably. Nowadays anxiety and depression aren't necessarily treated with medication. There are alternatives which I have seen mentioned on this forum... Even nutrition plays a major role in brain function and might be worth looking into.
]Thank God your mum and your sister are around. The next step is to want to live for YOURSELF, not for someone else.
I wish you all the best. Turn your life around. I feel you can do it!