re: so alone and so sad
If your wife is keeping your children from you, you need to go to the family court for enforcement. Take the court order that states that you have those hours per week to see your children, and they will provide you with help in seeing your children as ordered by the court.
As for your personal issues, I would continue to seek help from your doctors, and keep yourself clean and at work without any problems. Having a positive work history will go a long way in proving your ability to provide stable monetary support for yourself, and eventually your children.
While the months that have passed have obviously been very difficult for you, try and keep your mind on the future.
As far as the mistakes of your past, they are in the past. What really matters now, is your current and future actions.
Once you have shown you can be stable and are moving in a positive direction, you can petition the courts for better child custody arrangements. Make sure you are always there for your appointed visitation and make sure your wife also obliges with her court ordered visitation times with your children. If she does not make the children ready for you to visit, you can call the police to help facilitate the transfer of the children to you. Keep your court orders handy to prove your right to see your children. The courts look poorly on parents who deny their children the right to see their non custodial parents.