Hi...I haven't chimed in here so far as this subject area is my profession and, oddly, I've not wanted to go there....but.
Rich
You have more than enough on your plate to justify feeling pretty low and without energy or enthusiasm for life....it's an entirely human response to your situation.
In your shoes I'd probably be feeling the same and though, maybe, you'd score somewhere on a formal scale for 'depression' so would we all at times in our lives.
As for chucking it all in and hitting the road, that's understandable....though I'd caution against this right now. If it feels like ' running from' something rather than ' running to' something it might not solve your problems.
What does matter is that, if you let it, depressive thoughts will almost always lift in the end of their own accord....just takes time and good friends.
Get all the help and support you can find ...if you're having trouble with eating, sleeping or concentrating then maybe a trip to your Dr for some meds would be a help....after all if you're experiencing the above stuff it'll wear you out in itself...you need to be able to sleep well to recuperate.
Above all try to hang on to the belief that your mood will one day lift again....just not perhaps today.
My thoughts are with you.
Al