Today is one of those days

I want to cry and sleep all day! My 7 week old baby has gas and reflux. Went to the dr yesterday and he told us to give her mylanta 1.25ml 3x a day and gas drops. I stopped breastfeeding and went to once a day while supplementing with similac pro-advanced. at 3 weeks old, and now we stopped all together yesterday. I feel Terrible. We switched her formula also to similac sensitive. All she wants is to be on me fed changed or sleeping and when she is sleeping like right now, I have to clean bottles and after my 4 year old who just won't listen to me. I set up a pool for her to play in and she goes in and runs in the house or plays on a bike or gets into something she shouldn't. I also got my first period postpartum 3 days ago and it's so heavy and I'm crampy. I'm just exhausted and don't know what to do with myself.