Please help!! FTM

So my LO is 7 weeks old, I have been exclusively pumping & bottle feeding her. I tried around 3 weeks to supplement but she didn’t take the powder formula very well. (she only drank 1.5oz) She puked & pooped then slept the entire day from exhaustion.

This morning I tried liquid formula similac, which she only drank .5oz and were having the same reaction. But this time the last bit of puke was straight mucus... like, greenish!

How do I wean her off? What am I doing wrong? Why is she getting so sick just from 1oz? Should I take her to the ER rn? She’s back to sleeping rn but I am so worried!!