8 week old fussy on one breast

Julie

I’ve breastfed since birth, but since week seven my now 8 week old seems very agitated about 3-5 mins after latching on my left breast. If I switch him to my right breast he feeds fine. I haven’t felt any let down for just over a week now. Could my left breast be producing less than my right?

And should I persevere offering my left breast first, or express the left?