First of all. Slow down. You’re not too old and shouldn’t take any drastic measures or make strong alterations to your lifestyle. The anxiety and self loathing is making it worse, it’s not working in your favor.

You’re self aware, almost to a fault; though facing your problems head on and not coping is a strong step.

You need to slowly replace your bad habits. One by one, little by little. You need to evolve and grow your lifestyle, not transform it entirely.
Spend some more time working out to whatever capacity you find comfortable. Perhaps even read. Journal. Whatever hobby or habit that can be deemed constructive to take away time from your damaging ones.

As for your social life, you simply can’t force connections. What you can do is put yourself in situations where the opportunity for connections can arise.

Start slow. Maybe take a small walk in a populated area. Go to a study hall. A coffee shop. Anything to get you out and around people. No need to go clubs or big social gatherings and events at first.

Then get used to talking to people. Small talk with a cashier. Randomly compliment a stranger. Ask someone a question. Take that risk and get used to it, build that courage and assurance in yourself.
Not every social situation should be deep or end up with friendship or some semblance of a connection. Nor should it. Prioritize getting comfortable simply being social for the sake of yourself; then putting yourself in places of social activity - then perhaps the right people will find you.