Sorry you're having more issues Taurean!
Sounds like a good idea to talk about it with the GP. it could be... or it could be any number of things. She might just be getting quicker at feeding and more interested in the world around her. She might be feeling unwell. She might be going through a developmental leap.

Watch her output as the best indicator of input - lots of wet nappies? 200g in 2 weeks is just fine. remmeber to average weight gains over 4-5 weeks to get a better picture as they do vary a lot week to week.

Your supply will be more resilient than one bad day. Hang in there. Hope you get some answers/reassurance from the doctor.