One of the biggest things for me was to realize my feelings and emotions were perfectly normal. I felt like crap, emotionally and physically, but knowing what I was feeling was the way I should feel, helped. You're dealing with emotions that are truely foreign to you. It always helps to hear from a knowledgeable source. It eases the burden we place on ourselves.
Take care of yourself and the kids. After those two are in order, take care of the rest. There is no reason to rush just to get it over with. You have all the time in the world for the next step. When you get to a more settled state you will notice your emotions have far less influence on your decisions. As you move forward you will be entering a negotiation and the outcome will be far better if emotions are kept in check.
I still recommend a seperation agreement to the extent where finances and the responsibilities are defined. It is very common for seperated couples to get financially strapped and with out a sepration agreement you may be responsible for debt your H has incurred. The agreement may also spell out the schedule with regard to the kids. Think about it, it does help.
My offer to e-mail stands, if I can help at all off-line, don't hesitate. I've done it for many others and will for you.