5 month old not feeding properly

[KinderWild]

5 month old baby, BF has been going great for months. We've both recently had covid.

He goes on the boob to feed and sometimes I can't feel my letdown coming in. He gets frustrated, cries and comes off. I really don't think he's doing what he needs to do with his mouth to encourage the let down. This goes on sometimes for a hour. I keep putting him on he fusses, screams comes off. Eventually I get a big letdown.
Any ideas what is going on here. And it's it's me or him? Should say this one happens at night, sat after 7pm.

That sounds very stressful! A couple of ideas spring to mind:

Could he be teething? My DD suddenly became temporarily bad at latching as her first teeth came in.

Are you dehydrated? Supply can be lower in the evening anyway but keeping hydrated could help.

Are your boobs just changing? At 5 months mine started to settle down, much less engorged, less forceful let down. It’s a bit more work for DD but she learned to be patient. Most of the time .

Are your periods returning? My let down and supply seem to be lower in the days running up to my period.

I hope things get better - congratulations on BF for five months!

How are you both getting on now @KinderWild?