Baby prefers one breast over other

Jaime

So my little girl is 16 days old and I think has a preference for my left breast. She tends to feed on one breast for 15-20 mins, but lately when I try to get her to switch, she isn’t really interested or only feeds another 5-10 mins. As of late, she’s started to cluster feed but only after I start with the right and it’s mentally wearing me down. It’s tempting to just use my left breast exclusively, but I don’t want to ruin my supply in my right. I haven’t really used my pump much and when I have I know my right produces a third of what the left does. I guess I could start pumping the right more? Just looking for words of encouragement or any advice. Breastfeeding is much harder mentally than I ever thought it could be!