Very lonely mummy

Since when has motherhood been so lonely. I have 3 beautiful babies and in early stages of my fourth. But I’ve never felt lonelier. Don’t get me wrong I have my partner who is so supportive but it’s just not the same as having friends. Since becoming a mother nearly 10 years ago my friends have dwindled. I do suffer horrifically with social anxiety and depression but I can go days without having a friend to talk to too, because i literally don’t have 1 person. Please say I’m not the only one who feels like this.