How often does your dear daughter feed? Even though you feed on demand, you would have noticed a pattern by now, now that she's 7 wks old. Is it 2-3hrs?
You're right to pump after feeding in order to increase your supply. However you mentioned that your dear daughter wants to feed again immediately after that. That would be less than an hr since her last feed? Are you sure she really wants to drink or she's fussing due to other reasons? If she really wants to drink, then maybe her latch is incorrect so she's not getting enough milk out and gets hungry too quickly as a result.
Anyway, actually it's ok to latch her again after you pump coz technically our breasts are never 'empty'. After suckling for awhile, your body will make the milk required by your baby. That's also one way in which your supply can increase!