Until I joined this forum a few months ago I thought I was the only one who felt this way about my mother, but I have discovered that is not true.
34 years ago I realized with shocking suddenness that I did not belong on this planet and needed to exit as quickly as possible.
However, I looked around me and saw a devoted mother who would literally be destroyed if I took my own life. I know that sounds conceited, but it is true.
Cursedforever's post above is particularly important, I think. I know that my mother would drown in her "I-should-have-done-more/I-am-a-complete-failure-as-a-mother" guilt if I departed before she did.
So anyway, I made a pact with myself 34 years ago that no matter how desperate things became, I would not take my life while my mother was still living. After all she has done and sacrificed for me, that is the least I can do for her in return.
So, to the original poster, I would say please keep going. You will be saving your mother more heartache and despair than you probably realize right now. Obviously you love her a lot, so I can definitely tell you that, one day, you will be so glad you stayed alive for her.