Baby feeding from both breast to one?

My LO is 7 weeks and used to always feed from both breasts at each feeding (approx 10 mins on each side). However over the last few days she will only feed on one breast and not want the other breast after (10-15 mins total). So I started alternating breasts at each feed. Has anyone experienced this switch from their LO? Is this normal? Concerned she might not be getting enough. Thanks in advance!