Sorry if this is a daft suggestion, but have you thought of signing up to one of those 'pay as you go' gym networks such as 'Puregym' or 'Easygym' for when you're away? Get those endorphins flowing. If you don't have your kit with you, pick up a cheap set at a local discount shop wherever you're staying. It will take you out of the 'crappy hotel with morons' environment that you mention, and perhaps take your mind off other things.
There's also that Seasonal Affective Disorder thing (SAD) which, I think can affect more people than we realise. Obviously, I've no idea what you do for a living, but if you are stuck indoors for most of the week, a little outside daylight might help.
Whatever it is, I wish you well sorting it!