When is baby finished drinking

Marli

Hi!

My little boy is now 5 weeks old, going good with breastfeeding. Only thing is I am not always sure when he is finished drinking? I dont want to put a time in it, but can he still be busy after 40/50min(2 breasts). Sometimes he latches off, but then cries, then I burp, still cries and if I try relatching he is fussy or crying- is that from being tired? Is he finished? Thanxs!