Stopping breastfeeding for personal reasons?

I’m happy and lucky that I’ve been able to EBF my daughter for 5.5 months but the weight gain, giant boobs, and exhaustion that has come with it is weighing on me. I’m looking into stopping breastfeeding and going to formula soon. Am I crazy? Am I a selfish mom? Please tell me if you’ve had these thoughts about breastfeeding or if it’s just the past few sleepless nights that are getting to me...