Low supply- Pumping exclusively?

Do any moms in here have experience with exclusively pumping? My son is 3 weeks old and we are having an extremely hard time with breastfeeding. He had a tongue tie that we had clipped this past Wednesday and we have been seeing a lactation consultant. He just doesn't seem to be getting the hang of it. We've had to supplement with a lot of formula because he's been loosing weight. My supply is definitely on the low side because of the issues we've had. When I pump I get less than and ounce combined. If I begin to exclusively pump will my supply come back up or is it to late? I'm hoping we can work out our breastfeeding issues but if not I still want to be able to give him my breastmilk.