Making Friends

I have depression and I just recently realized that I have isolated myself. I am a stay at home mom, so no work friends. I have my hubby and 3 young kids, but zero friends or people to vent to or go out with. I didn't know I had done that until my therapist pointed it out. What do I do? How can I make friends? It's not like it was when I was in school and you just happen upon people you like to hang out with. I stay home all the time and if I ever go out anywhere I'm either with my family or by myself. I miss the days where I had close friends. 😢