Oh, hang in there Saluka! That's a big pile of stress and worry. And yeah, those stress hormones are a nasty piece of work, can affect your health, your appetite and yea, your libido as well.
Paradoxically a good sex with orgasm can be a great stress relief, but the problem, of course, is how to have a good sex when you are too stressed to have any sex.
Perhaps have a talk with your man again and explain the situation fully (and I don't mean how busy you are and what pest he's become, but how stress has robbed you of your desire). Maybe he just can't understand, because maybe for him it doesn't work that way. Maybe the lucky devil gets more horny when he is stressed. Maybe he is actually TRYING to get you to relax by having a good romp (could be even sweet of him, no?) Try to make him your ally in this. And if you get to do it, see if instead of trying not to be distracted or preoccupied by all that's on your mind (that's like not thinking about the elephant), you can take it all, all that stress, all those deadlines, all those frustrations, all fears and worries and just feed them into your sex, like having a one great "f it all!" moment, a rebellion, a Mel Gibon screaming "freeeeeedoooooom!" moment, a catharisis.
And if not, just hang in there. Have faith in yourself. "This too shall pass". You're gonna make it