Asking for my mom who is 60. she is having a bad reaction to amoxicillin that she took a few hours ago. she started off being hot and sweating a lot. then she started have diarrhea and vomiting a lot. now she says that shes cold. what should i do?

This does not sound like any typical reaction to an antibiotic, but more likely the underlying illness she started the antibiotic for is getting worse. Would call the doctor who prescribed the antibiotic. If this is not possible, she should be rechecked by her usual physician tomorrow, right away when office opens. If symptoms worsen, go to ER tonight.