There may be some clips underneith (or places where they should be clipped to) that will hold it down. Clean the matingg surfaces of any debris and wipe down w/ denaturred alcohol and reattach/glue with silicone caulking. Caulk around the edge of the sink and countertop with a nice bead and let dry. Make sure the caulking you use is acceptable for laminate and stainless or porcelian or whatever the sink is.
Good luck w/ the house