Fussy over boobs

My baby will be 6 months next weeks. Since last 3 weeks she is being fussy while feeding over both boobs. When she latches and flow is good, she happily drinks milk but once the flow slow down she gets fussy, cry a bit and come back at it, sucks for 2-3 seconds and repeat the cycle. Sometimes she also squeeze my boob( which is hell a lot painful) I burp her in between the feeds and also change the boob side. Again she gets good flow from the other boob but once let down slows she just screams. Initially i was feeding her from nipple shield till she was 5 months, but one day she just removed it herself and latched without it. Is this normal or just a phase? Do i need to see lactation consultant? Sometimes i feel if she is getting enough and hopefully is not hungry? Anyone else's baby like that? Any advice is appreciated.