hi guppyluvr,
sorry 2 hear that. most of the reason for death among guppies are the water. kindly check your water in your tank. Is it properly condition (with anti-chlorine & salt)? Is the filter in good condition (the filter wool not brownish/running smoothly)? Is the water clean (no or little waste at the bottom)?. Maybe u can search thru the Internet on how 2 maintain your tank.