You don't have to love your mum, and as long as you are convinced that you do have to, you're going to have a problem.
Your mum is a an individual in her own right, and will behave however she wants to. She may have been the best mum in the world when you were little, but since then she has changed to the kind of person you would probably avoid like the plague if she was just someone you'd met and got to know recently.
So, recognise her for someone you don't like much and may well not love, but do have a special link to anyway, and stop beating yourself up over what you said about her. Give yourself a break from her (meaning don't get in touch with her for a while) and take some time to think about how you can manage to have a relationship with her while still living your own life and having your own friends.
For what it's worth, my mother told me, when I was in my 20's, that I had always rubbed her up the wrong way. I'd realised long before then that I didn't love her, and that there was something about me that she really didn't like much. I respect her for who she is and I always give serious thought to any advice she may give me, but she still annoys me at times, and at times she can be downright nasty, but we manage to get along most of the time, with both of us living our own lives.