Baby making me crazy!!!

My baby is driving me insane!! She cries and cries and cries somemore. I took her to the pediatrician today because she wasn't pooping like normal and would spit up a lot of her milk after she finished eating. They switched her formula from sensitive to spit up. I made her a two ounce bottle and she was still hungry so I made her another two ounces. She's eaten, been changed and ready for bed. But what is she doing right now? You guessed it crying.. my boyfriend and I are exausted. I need some advice ASAP! I was thinking of getting her a swing, maybe that will calm her into going to sleep at night? Please lest me know anything that will help! Thanks in advance.