Zofran?

I'm sick as a dog,nauseated and puking several times a day. Can't sleep and can't hold down food or drink. My preggo SIL gave me her last 3 pills of Zofran (4mg) and I've taken them once a day and it's worked like magic! I'm out and ready to go to the urgent care in order to get some more to help, but after some go ogling I'm a bit concerned.. is anyone here on zofran? Are you concerned about the lawsuits? Or the birth defects it may cause? I'm so nervous but so sick too. Help!