Spitting up & vomiting

My daughter is 4 weeks today!  She spits up a little after every feeding and has ever since we had to start formula at 2 weeks!  She has to where she will throw up a ton as well every day or 2 after a feeding!  It is not more than 1 feeding a day but it is so much!  I have mentioned it to her Dr and they say it's normal because formula is crap!  I get it!  I breast fed for 2 weeks and my milk decided it was gonna dry up all on it's own completely so I had no other option!  I'm just not to sure what to do!  She gets to where sometimes she acts as if she is choking out of no where!  Like a hr after she has ate she does it several times sometimes she throws up from it sometime she spits up from it!  She still sleeps a lot!  I would say some days she sleeps 18 hrs a day and some days 20-21 hrs!  Dr just says she is lazy!  Any advice would be greatly appreciated