I went from mixed feeding to exclusively breast feeding. I had been pumping and mixing EBM with formula and not directly breast feeding at all (due to PND & sore nipple issues), DD was taking 4-5 oz every 2-2.5 hours. I was trying to increase supply to all EBM and less formula but wasn't having any success as I don't terribly well to pumps (and what you pump is not as much as what a baby can get out).
Decided to move back to actual breast feeding once I was better, so sorted positioning and latch with help of Youtube and BFN, then every time DD seemed hungry I put her to the boob. When she fussed or seemed to be finished, I burped her and moved her to the other boob. Kept doing this until she wouldn't take any more boob (some feeds she'd only have 1st side, sometimes 4 sides!). This is called 'switch feeding'. Your boobs are never completely empty, they constantly make milk even as milk is being removed, and the emptier they are the faster they make more, so this is a great way to boost supply.
I pumped in between feeds too and took fenugreek to try and boost my supply further.
We also did lots of skin to skin, she spent several days laid on me with me on the sofa just feeding, feeding and feeding some more.
First few days she had a couple of bottles when she wouldn't settle after lots of breast and I was sore, then I dropped those completely. We were EBF within about a week :D She fed very frequently at first, then things settled down, she can now go up to 6 hours overnight without feeding (usually 5) and anything from 1-3 hours in the day.
So yes, it's perfectly doable. Good luck! :)