So, I was a single mother for the first eight years of DD's life. Then met DH. Got married. Realised it was a big mistake and split a year ago. Now just DD and I again.
In those years I have learnt:
Being single can occasionally be lonely. However, I relish having time to myself, I work full-time, so evenings and weekends are great for me to chill out, hang out with DD, see friends, see family. Lonliness really is not an issue for me.
There are some people in this world who do, for reasons best known to them, think that single mothers are predatory females who want to steal their husbands. However, such people are generally twattish and if they truly think that, then they're not real friends. Some of my best friends are married and totally normal and do not see me as a threat.
Similarly, some guys aren't keen on dating women with children. But then again, hypocritically, I'm not keen on dating men with children, even though I have a child myself.
I have no regrets about leaving DH. It was tough at the time, but the lonliness and misery I felt in that marriage was far, far worse than any unhappiness I've felt being single. I am so glad that we broke up - I'm so, so much happier now than I was being married. Staying in an unhappy marriage is soul-destroying.
Good luck!