I had just quit my job to join my boyfriend, who had just started a 3-year graduate program, when we found out I was pregnant. I was extremely stressed out for awhile, realizing that all our plans were upended. But as a PP suggested, look into the programs in your state and start planning. I found doing these two things helped out immensely, and relieved much of the burden I felt.
Now I count myself lucky to be in New York, which has a MOMS program that provides Medicaid for me through the pregnancy +3 months, and the baby for an entire year (after which we would have to requalify). I have taken advantage of a lot of programs here, and every one helped to lighten the stress. There's WIC, heating assistance, dental care during pregnancy, and food stamps. Free car seat through his school. And I haven't even applied for the air pollution and energy appliance programs offered, nor have I visited any of the pregnancy counseling places around here that offer free baby gear. My point is that there might be a lot more available to you than you may think, and they all help.
There'll be an adjustment, no doubt. I've started stalking FreeCycle in my city as well as Craigslist free stuff. I've given up most of my attachments to having cute, new baby gear. There will be no baby nursery, and we're staying in our 1-bedroom apartment for another year. Things won't look like how you imagine, but for me at least, I'm happier now than ever, in part because my (admittedly enforced) minimalistic lifestyle allows me to focus on the important stuff.
Also, I was able to get a part-time job at a food co-op even though I told them on the application that I was pregnant. It's not the college instruction I had been doing, but that's okay. And it doesn't bring in a lot of money, but it has flexible hours and allows me to feel less powerless. Having a little income stream is good psychologically, I think. (But don't feel bad if you can't find work. I was again lucky, in that the hiring manager at the co-op is pregnant herself. I also applied strategically only to two places that seemed mom-friendly and open-minded so it wouldn't be too discouraging.)
Good luck!
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