advice?

Hey mommas. I have a now 6 day old. Our first few days in the hospital and home she was nursing constantly if she was awake. I know this is normal. She would cry like she was starving if she wasn't latched though. The lactation consultants at the hospital said her latch looked good. Our first doctor visit Wednesday she had lost almost a whole pound so the dr asked me to nurse one side 15 min, the other 10, and give her 1oz formula after to help her gain some weight. She said to pump and if I could pump an oz I could give that instead of formula. So I started pumping and feel like I've had increased fullness finally-I've still had no "engorged" feeling. Most of yesterday I was able to give her only pumped milk. Now she's wanting to eat a little more than the oz after nursing. I can barely pump the one oz for her though. I've been drinking water and mothers milk tea. I hate to pump more often and be empty when she is ready to nurse. Has anyone rented a hospital pump? I know they are supposed to get a lot more milk out. I thought about doing it for a week to see if I can get a better supply going for her and possibly build a stash if we still need to do some pumped after feeds. The pump at my hospital is only $25 but the kit to go with it is $45. Or does anyone have any other suggestions? I think the pediatrician (we follow up today) is wanting to get me in to see lactation since there won't be much improvement with my supply but any other tips would be great until then. Also instead of 15 one side, 10 the other I put baby on one side 25 min and pump on the other 25 and alternate each feed. Is this a bad technique? It is easier not having to pump as well after feeding.