hiya, very happy to be SAHM!!
Def agree that it's critical to get out of the house every day and at least once a week get someone to look after LO (I do half a day at nursery a week but you could also consider a sitting circle or posting an ad for such light childcare at your local post office). I use my afternoon a week to indulge in whatever -- coffee and a mag, manicure, extended shop, reading intellectual things without interruption, planning special gifts or dinners, etc etc.
Consider finding exercise classes with creche in your area. I hope to get back into running after babymaking is out of the way and it's enormously mood lifting.
Perhaps it's just been a hard day/week - we all get those. And it will take some time & pondering to figure out what to do now - after prioritising the job, or DH, or the baby, it can be difficult to remember how to think of what YOU want!
For waht it's worth, I had v similar feelings to you when pg with DS1 and had to give up work early due to major pg sickness. I needed medication in the end for prenatal dep and a few counselling sessions - is it something you considered? I used to be very job-focused so it was scary to leave it, but in fact that job didn't make me truly happy at all. Best thing that ever happened to me was being 'forced' to leave it!
So what do I do now with my fancy degrees? Well I've made loads of wonderful friends via DS, and I'm pg again, so that's me occupied . After this one comes, I'll be starting pottery or painting or maybe cooking classes, because these are things that personally make me happy. Whatever I do, you can bet it won't involve schlepping into a job to work for someone else!! Those days are OVER!
The very best thing about SAH? Getting all the smiles and giggles. Better than a sodding few quid a month after childcare if you ask me! And wait till they can talk...