breastfeeding/ pumping schedule

Ni
I was EBF until about two weeks old when I began to introduce a bottle, but I had been pumping since about day four of my LO's birth. Now I want to introduce her more to bottle feeding (she's almost 4 weeks old) since before I was pumping multiple times a day but only bottle feeding her about once a day. But now I feel if I let her breastfeed and then pump after I literally have no milk left to pump! It's like I have to skip a breastfeeding session and pump instead so that I can have enough milk supply. Basically what I'm saying is I don't seem to have enough milk to create a "reserve" for her, in case I leave her with someone else for a few hours without pumping beforehand. Any advice on how I can create a schedule that works? I'm also worried in general about my overall supply as it doesn't seem that high and I know she's going to want to eat more and more pretty soon.