My granddaughter has been on sulfameth-trimetho cherry for the last 4 months & is only 8 months old. Her doctor says she's on it to prevent infection but doesn't know what kinda infection she has, or at least isn't telling my daughter. If my daughter misses giving her a dose she gets a temp usually around 102 & starts to vomit...What should we do? We want to know what is wrong with her.