I'm going through this phase right now myself.
First thing to do?
Realize who you are. Go over all your past achievements, awards, goals you met.... etc...
This time will most likely test your faith in your own capabilities. Which the tone of this OP sounds like it has been shaken.
Second thing to do?
Make a plan. How are you going to IMPROVE yourself?
Whether this be working out at the gym harder, new haircut, pampering your skin with special lotions, going to get microdermabrasion....
Third thing to do?
Find an activity, or many activities to do.
I personally suggest yoga, Ashtanga is what I chose to do, and took the skills I learned in course to become my stretching routine after each workout.
Realize that if you're going to go to try and meet new friends, you're going to need to emerse yourself in an environment that has people of that interest.
If you want someone that is into tennis, play tennis.
If you want a muay thai enthusiast (I am one), then find a gym that teaches muay thai and prepare to scream at your shins...
Fourth thing to do.... and constantly throughout!!!!!
Never lose faith in yourself. You needed to clean your life out of people that were damaging and hurtful. This is a move FORWARD despite what your heart might be telling you.
Just stay strong, everything WILL get better- just put in an effort!