If she falls asleep at the boob, it’s most probably comfort latching (human pacifier). You can roughly gauge how long she suckles then detach when she falls asleep.
It is also normal to pump only a little after latching. If you’re trying to build up your supply, just keep pumping and latching. Overtime it will increase. Can also try latching > pump, baby sleeping maybe after an hour > pump > latch. If too intermittent feeding then just pump after latching without the additional pumping in between.
If you set your mind and confirm you’ll only breastfeed, can join the BMSG group on fb. *Do note that this is not for you if intend to mix feed.*