What questions would you like assistance with?
You would do right to set limits. Better now then never.
No one should mistreat another. If he depends on you for anything, then yes, tough love is better than enabling further.
Your son may be sensing your fragility and taking advantage of you. If you continue to go along the same way, he will remain the same.
If you feel overwhelmed and stressed out, getting some supportive counseling for the time being.
Not sure what help could be offered on line (but there are free on line support groups as well) If you were wondering if you're the right thing- you're on the right path - you need to find a solution and a way to deal with what is going on. You would also need to surround yourself with positive supportive individuals. Meanwhile, just deal with one day at time.