You should follow her cues and if she seems able to go longer, then let her go 3.5 hrs between feeds.
Pumping off the first bit of milk will keep the supply up, but your little one won't get the gush of letdown. Again, women say nursing from a laying position slows the letdown so the baby is not overwhelmed. The baby can't regulate letdowns, only the amount they get into their belly. Fast letdown usually leads to gas issues as they gets into them too fast. Some babies actually sputter and choke from letdown. But again, do you know if you have a fast letdown? If you don't than this wouldn't be the problem. You could used the pumped milk for a dreamfeed, or stockpile it for a night out, etc. Have you tried the football hold? How about walking around with her in a sling?
It could be related to the dr's office, but that's a bit out of my reach of knowledge. Also, around 2.5/3 month mark, the soothing properties of my breastfeeding quickly dropped. Maybe it was just a coicindence that happened.