I'm sorry that things are going so poorly. It sounds like Sam is having a tough time of it. Drug use is not a good sign and it seems Dave has had an influence on how Sam copes with his stress. Do you feel Sam would accept help for his drug use? It may be good to try to introduce it to him to see his reaction.
I know that the last thing you need right now is more stress through Sam acting out. It may help to just take one step at a time. Deciding if it is more helpful to you to deal with Dave first then Sam, or vice versa. Part of the solution can be to decide what steps you want to take next in resolving some of the situation you are in. It may feel overwhelming to look at the whole problem, but we can break it down and take steps to allow you to feel like you have some control and that you can progress.
This is a lot of stress on you, Rose. You are acting as a single parent here, and coping with the children and all their needs and you are dealing with Dave, who is abusive and not responsible. What do you feel would help you most? You mentioned taking some medication to calm yourself, so you are feeling so stressed that you don't feel you can cope. That means we need to come up with ways that you can use to calm yourself, without having to take medication. How about some of these ideas:
Call in all your supports. Seeing Adele tomorrow will help a lot. When you see her, try to find out why her emails won't work (I know you'll do this anyway :) ) and tell her how important it is that you have a way to talk with her in between sessions.
Try K if you feel ok doing that. Let her know that you are looking for ways to calm yourself and focus on progress.
Listen to your tapes, and practice your progressive relaxation and breath. Sometimes in all the stress, it is hard to remember to take deep breaths.
Accept that this is a rough patch and that you will get through. It is awful to cope with, but it will pass.
Talk and talk some more about how you feel. The more you express your feelings, the less burdened you will be.
Be sure you are nurturing yourself. Don't forget that in taking care of others, you need time too. Plan something nice for yourself each day if you can.
Don't lose hope. You have come so far and you can see this through. Try not to listen to anything negative, especially from Dave. He is insignificant anymore in your life. He is on his way out. He is not your source of self esteem, you are. You are a wonderful person that is giving, strong and compassionate. Repeat that to yourself as much as you can.
I'll be here tomorrow Rose so if you feel up to talking we can spend some time together.
Just to let you know, I will be away from my computer from this Sunday May 13th to Wednesday May 16th. I will try to check in, but I'm not sure I'll have access to internet (out of town trip). I didn't want you to write and not be able to get a quick answer. I may not be on at all on the 15th. It's a special day (wink, wink!) and I may be busy all day. But I will try to check in at least once on the other days. I want to talk with you and I'd miss you if I couldn't :(
Talk to you tomorrow,