Question for breastmilk fed

I'm debating whether to stop pumping. My baby has been exclusive breastmilk until a month ago. I only supplement one bottle a day (doctors orders), but I spend at least 3 hours a day just pumping; with my job and older kids, I'm just totally wiped out. When someone suggested going to formula only, it was a relief to hear. It hadn't crossed my mind until then.

When did you know was the right time to go to formula only? Or how did you push through with nursing? Was it worth keeping in it?

Side note, I had a miscarriage this month. Could that be effecting my energy levels, and will resolve next month?