I felt that way with my last job. In fact, I kept getting migraines because I was so depressed and angry about my job that it manifested physically. I'm sorry you're feeling this way

Thankfully I found a great job and I've been there for 4 years, but I totally know the feeling of just DREADING work.
My only advice is to try to look at the positive aspects, and stay optimistic that something will change. I'm the breadwinner in my house too and it's STRESSFUL being a momma, working full time, and expecting another LO.
Is your work covered under FMLA? If so, consider talking to your doctor about changing your duties or schedule. If you're eligible for FMLA coverage, your employer can't eliminate your position or retaliate against you for anything that happens relating to your pregnancy. They have to hold your job or provide one similar upon your return, and they can't fire you if your doctor writes a letter restricting your hours, days, or duties. I don't know what you do, but it's something to think about. Some money is better than none, and maybe a reduced work schedule would help you not feel quite so burnt out.
I also had to return to work after Kawika was born (9 weeks after) because my short term disability payments ran out and I couldn't afford to take the last 3 weeks of unpaid leave that I was allowed to take. I worked out a part-time schedule with my boss. I was still entitled to 15 days unpaid leave so I worked a reduced schedule, like 3-4 days per week and had 1-2 off, unpaid. It wasn't great, but some money was better than none, and some time at home was better than none. It doesn't hurt to ask your boss what your options are for after your leave. Also, if you haven't, talk to your HR department about what exactly your options are for leave. Info is a great tool (and weapon, sometimes).
HTH. ((BIG HUGS)) Chin up. Before you know it, you'll have your LO, and everything else will seem much, much less important. It's amazing what you can put up with when you've got something so happy in your life.
Julie (28) DH (36).
^i^ May 2010
PAL grad! DS Kawika born 4/25/11
EDD 10/7/12, Blue Team!