It's okay,
First, I want to welcome you to the stress center. I think you are miles ahead of the problem. With a slight exception, running from the problem is impossible. In the first paragraph of your post you fully understand the source of your problem:
I exhaust myself with my own thinking to the point of being so overwhelmed I swing to the opposite extreme and get depressed like I am right now.
The best thing you can do is confront your problem. You already understand that you are the source of all the thinking that makes you feel as though you are losing it. You are not losing it. You control your mind and your thoughts. It is clear to me you understand that. Next, stop beating yourself up and go easy on yourself. Yes! be kind to yourself !! It starts with you and you can put an end to the swings that make you crash.
If you have gotten the program and have learned the breathing exercises; start there. If you have faith, take hold of a Bible and prayer for divine guidance before you open the book. If you have no faith in God, then you must have some faith in your self sufficiency, sooner or later you will find out that God is real and He is the one that inspires you to persevere. Sorry, if you don't believe it.
The universes and all that is in it were created. Here's a thought, what ever comes of disorder remains in disorder. I am speaking scientifically here. Look upon the universe and all that is in it, and the more you study it the more you see order. If you still want to believe in big bang; you have to think what sort of bang could have set the universe in the order and balance that it appears to have and is continually being discovered? Perhaps a calculated bang? Calculated by who? You see the more inquires that are conducted by science in their attempt to disprove God, the more they find out what I just took you through. God is! Is. 66:1 and Acts 7:49
It's okay, believe me it is going to be okay. Trust me. The longest journey begins with the first step. If you want to find out more, the answer is not in 1,000 jars of medication, as they only serve to conceal the problems or make them worse. It begins with you, it should be clear to you that you can not continue without God's help and guidance.
I will pray for you and for God to grant you His peace so that you may begin to live the life of joy that God intends for you, and usher you into the life of abundant living in and through Him. You will realize that He is real, He cares for all of His creation and that includes you, and when you do your fears, and all your mountains will disappear or at least not seem to be as big a deal as you empowered them to be.
I hope that you are ready to discuss more. May God bless you with His love, mercy, forgiveness, grace and peace; according to His riches and His will, In Jesus name I pray. Amen!