Is there blood in the stool at all? Did they check for microscopic blood? I just ask because if so he could have a milk protein allergy and if that's the case you need to not eat any dairy while breastfeeding.
Diarrhea is a sign of intolerance. He may have trouble digesting cow's milk protein. You might have to take him to the Dr for formula recommendations. I'd either be soy or a formula that has partially digested milk proteins already. If you can start breastfeeding again i say go for it. Less of a hassle. Good luck hun
You may have a good try at pumping if you find that he is having a hard time latching on! Breast milk will be so much better for him. Also to increase your supply you can try mothers milk tea, lots of water, and oatmeal.
I'd say try the breast feeding again but he get confused with latching on because it's different with a bottle, also change his formula if he's getting diorreah everytime
He just turned 2months today