How to prevent bed bugs from getting on me? a bed sack?

Probably not: The only way to prevent bed bugs from getting you is to sleep in a place without bed bugs. I know that sounds glib, but it's true. If you have bed bugs in your bed, get information on extermination. If you're worried about a hotel, etc., it's luck of the draw.

Bed bugs: Agree w dr. Mays. If a bed sack is a sleeping bag- that won't protect you. If a bed sack is an airtight mattress cover- that will only protect you from the bedbugs that are contained within your mattress (& trust me, they will be hiding in more places than your mattress). They will need to be eradicated professionally or by you. See: http://treatmentforbedbugs.Com/.