I understand and sympathize with you. For me it was the opposite though. I had my children very early in life while my peers all waited quite late to start their families. Many friendships just fell away as we no longer had anything in common. Now things have reversed. My children are grown adults while I have friends whose children some of which are still in diapers. It is all very hard to socialize.

But this is what I did when I was mom alone with young children. I could not afford babysitting so I found things to do with other young moms. The local fitness facilities and recreations centres were my primary sources of socialising and establishing new connections. I found mother/child courses whether they be fitness related or otherwise (ie. arts and crafts classes, etc). Often, socializing would follow such outings such as heading out for coffee, etc.

Today, in the age of the internet and social networking, I imagine it is easier. For example that meetup.com mentioned above is a fabulous way to meet new acquaintances. In the meantime, visit community halls and rec centres and check-out the notices for groups, etc.

Finally, if you haven't done so already, become involved with a support group. They often have a social component to them.