Breastfeeding advice!

My daughter is 1 week old and suddenly seems to have a problem latching to my left breast. She latches well and drinks from my right but has suddenly stopped doing so from my left. Does anyone have any idea what could be going on?
She previously latched well on both sides but now on the left has one or two sucks and then let's go again. It's not an issue of no milk as I expressed from my left earlier so as to stop myself getting engorged as it was starting to get uncomfortable!