Lori--
I don't know how much these ideas will help, but anyway..here I go....
Have you thought about joining a local gym (maybe even one that's all female if there is one in your area)? You might meet some people in an aerobics class, but I don't know how friendly and open your town is. Even so, it will be something to do while your son is at preschool and it can help you feel better about yourself (and you'll look even better too
)
Maybe there are places around town that need volunteers. Again, something you can do while your son is in preschool. You will meet lots of people this way and you are bound to find a few that you really click with.
And my last suggestion...I don't know the format of your son's preschool, but maybe they could use some help too. You know how there are always "class moms"? Maybe you can see what you can do to help the teacher. Additionally, you can see who your son's closest "friends" are and invite them and their moms over one afternoon for a play date. This will give you people that are probably somewhat close to your age to spend time with, as well as helping your son build relationships outside of the classroom.
I hope this helps and that your situation gets better
By the way, what part of the country are you in?
Melissa