Pumping and BFing is hard work but you have to sit and think about what's best for your LO. it takes a lot of dedication on your part with time, watching what you eat and put in your body. There is nothing wrong w/ FF or BF/pumping AND FF. I EBF for several weeks and eventually began to supplement w/ formula bc my LO wasn't gaining weight so we didn't have a choice. She just went exclusively to formula yesterday (except for solids, too). It was emotional for me but it's a choice you have to make and decide whats best for you and your LO.
Now, if you choose to continue pumping you have to be very consistent. I did it every 3 hrs MAX 24 hrs a day. That meant setting my alarm to get up in the middle of the night to pump since LO was STTN at 12 weeks. I pumped 3 times a day at work (which sucked but I had to!), I took fenugreek, drank mother's milk tea and ate foods to increase my supply.
Good luck in whichever you choose! :)