I would recommend doing voluntary work. It provides a routine to your week, you meet new people, both the other volunteers and those you are helping, obviously depending on the context. You learn new skills or put existing skills to good use.
Or join a choir/ netball team/ dance group , whatever you are interested in. Get involved in running the group.
I have made lots of new friends, through, choir, church and volunteering. They may not be ones who pop round for coffee, but they are a valuable part of my life, and amongst them are those I could turn to if I needed help.