The hard part about those meds is that it can take some time to get them zeroed in where they work best for you. Honestly the best resolution for this doubt and fear you have expressed is prayer and fasting until God does something in your life. See, dealing with doubt and the other things you are struggling with, while there are some medical steps to take, are beyond what you can do yourself. This is the time when you need to rely on God the most. Paul said when he was weak God is strong (in Paul's life). I think there are some real possibilities for you here:
1. You will learn about God in a much greater way through prayer and fasting until He answers.
2. Because you are at your weakest state God may use you in a huge way to glorify Him in the lives of others.
3. God may show you something that will forever change your life.
As you go through your days be in constant prayer no matter what you are doing. Be available to be used by God in what ever way He sees fit (i.e. witness, minister to, others). The great commission tells us to "Go". That means "as you go" in other words as you go to the store, as you go to the hardware store, as you go to the park, as you travel from one state to another etc. Be ready, be in prayer, and find as many times to fast food, or other things of pleasure as you can all the while you would have been engaging in those activities pray instead. Continue this process until God makes this trial you are going through clear.
I promise this will work.