First off I would like to say that if walking helps, keep doing it. Do those things that help you deal since you can't be on your meds.
Second talk to your dr. There are some meds that are ok to take during pregnancy to help with anxiety and depression. There are ladies on JM and those I know personally that have done it and had perfectly healthy babies. It might help. PPD is nothing to mess around with and you need to make sure that you are taking care of yourself.
If you need to pass of the bills do so. You have enough going on, and it sounds like it might help DH see that you need to change something. Are there any PPD support groups in your area? I don't like counselors either. Please don't feel alone. I have been that far in the darkness. And it wasn't because I wanted to go away, it was because I thought they would be better without me because I was a mess. I now have my children's names tattoo'd on my inner wrists to remind me that they are worth living for. No one except DH and my best friend in Alabama know the reason I put there names there. Well and now you and whom ever else reads this

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Maybe you could try journaling, that can be very thearaputic for many people. I found excersice has helped me among other things like meds. Sounds like your DH is very supportive. I know family can suck sometimes. When my family starts to drive me a little bonkers I pull my DH and kids closer to me and push them away until I am ready to deal with them. If you need someone to talk to we are here. This isn't the mose active board but many people pop in and out. You can PM me anytime if you just need an understanding ear.

you are not alone.