You'll get a lot of good advice here from people who have a lot of experience. The thing to keep in mind is that everyone's situations are slightly different - but the overwhelming majority of things that take place in everyone's relationships are very common.
Take time to breathe every day. Are you interested in meditating? It has helped me calm down greatly and it has eased my anxiety. I also have PTSD from my childhood and from the military. It has been significantly reduced by meditating. It is hard to do at first, but you will notice its effects after a week or so.
Also - if you find yourself starting to feel emotional around your W - remove yourself from her vicinity and get emotional somewhere you can be alone. This takes some getting used to but it is a good habit to develop and it will save you the indignity of seeing your W get disgusted with your feelings.
Realize that she is not having the same feelings as you. In her mind there is no R anymore - she has moved on already. This is hard to accept and it will take some time, but the sooner you can accept it the better you will feel.
Your emotions will be on a rollercoaster for a while. Controlling them is a struggle but it can be done. This takes time. Be patient with yourself and take care of yourself.
I see you are in IC - that's a good thing. Keep going. It will help you greatly.
If there are any questions you have feel free to ask. These are really great people here who want to help you.
