I have had such great advice here. I must be the biggest idiot ever, though, because I can't seem to do it. I can't seem to make goals for me or imagine this as a great new future or even work on liking me. I am stuck in the past and the future seems so bleak. I'm just so stuck and I'm scared and so so so so sad.
Do not stress about this fact in the slightest my friend, not for one second! I can tell you from personal experience every word of this paragraph expresses exactly how I
felt shortly after my separation.
In my first session with a therapist I was really upset telling her I didn't know who 'Ahoy' was anymore! I didn't know me, my interests, my hopes and dreams, why I bothered getting up in the morning. As you say, I was completely stuck in the past trying to grab that feeling of a happy marriage with both hands.
Yes it is a REALLY sad and terrible time but guess what, one day I literally woke up, got out bed and realised I was still the same person! I had a moment of clarity where I 'found' myself again, or more to the point I found my hopes and dreams were still the same now as they were before, just some minor details of my dreams had changed (table for two is now a table for one

). I was so excited I called my core-support group to tell them I was still me.
Personally, 'losing' my identity in this separation was the most terrifying thing, I think it directly relates to how much of ourselves we are pouring into the relationship during the final stages, simply to keep it afloat. My whole way of thinking had changed from how to make us happy as a couple, to how can I make her happy, she came before everything.
I did exactly what HurtinNW did, I sat in the damn bath and read (and read, and read, and read... .) till the water went cold, then I ran another bath. Nothing is going to speed up this period sadness (you are mourning the loss of your relationship) but gaining knowledge sure helps soften the blow.
I'm saying this with 100% confidence, do not fear the loss of your passion or ability to set goals. You WILL get your mojo back, just take things one day at a time until you do.