Hi,
20 mins is just a guideline. Your baby is a bit older now - 7 weeks or so? he is probably a pretty efficient feeder and can empty a breast in no time. If he falls asleep a bit earlier than 20 mins take him off (put your little finger in the corner of his mouth and gently break the suction - his eyes will spring open and he'll suck like crazy - as though to say "please don't take me off" but do anyway. Burp him and change his nappy to wake him up a bit and then give him the other side - same - no more than 20 mins. It's probably more important that he gets more feeds, rather than longer feeds - most babies need at least 8 (even 12 or more is normal) If he still seems unsettled you could give him both sides again - often babies stay a bit more "interested" that way.
If you pump after the baby has fed it will stand to reason that he's finished most of it - so you won't get much then. If your baby is keen to feed it's usually not necessary to pump.
Glad you're feeling better - you've had a very hard week. Look after yourself.

