SAHM, miserable and alone!

Ever feel like you have no one? That's me. 
I became a SAHM in April. I had 3 kids at the time and had just learned that I became pregnant with my 4th baby 2 months post pardum. Surprise. I had a great career, but I was already struggling with stress and depression that I could not go on. My husband supported my decision. Now we live on one income which is very hard. We are struggling. I am 35 weeks pregnant and I am in a lot of pain each day and also have to care for my 10 month old who crawls everywhere and also wants to be held. All my friends were from work and I see no one now. I can't afford to go out and I don't feel like it. I have no one to talk to. I started therapy a few weeks ago but I am still so depressed. My best friend is my 12 year old son. He listens, helps me and loves me unconditionally. My husband is tired after work and wants to concentrate on the kids and not my issues. Anyone else in a similar situation? I feel like I need to place an ad in the paper asking for friends. Lolol which is crazy. BTW I have no family around.