Drained,
Your feelings are normal, for someone thinking of divorcing. Even if it wasn't an addict you wonder how am I going to pay for this or that. How am I going to support my kids etc. You will do what you need to do when you are ready, and it seems like you are working on it now. You are doing things to help you in the future, posting resume looking for another job, looking into teaching. They are big steps even if you don't think they are yet. You are moving forward, yes you are still with him, but you will know when YOU have had enough.
Know that we are here for you,
Hugs coming to you