Actually the way you’re doing it is good, because when you latch on, your baby will just drink what she needs and then stop. They do cluster feed sometimes, so this 5 minute thing is possible:) as long as she’s not throwing up or uncomfortable, it should be alright to feed if she’s hungry. Also, do check that all her other needs are met, because she may also be tired/scared/insecure/uncomfortable:)
Babies will stop when they had enough, I think