I need to stop breastfeeding. How do I stop?

Breastfeeding is taking a major toll on my mental health I'm being coming more and more suicidal everyday that I do it and I need to get the help I need. I need to be able to take the medications I need to get better so I can take care of my baby. Breastfeeding is ruining my life and making it harder for me to be the mom I need to be. I feel like a horrible mother, I've only done 4 months and I feel like an absolute failure. What are the best ways to stop breastfeeding, please help.