Jeeze Strecing Jeans!!!! HELP!!!?

well all my jeans are a little bug becasue i lost a few pounds, and they are like 1 or 2 sizes big, and they are tight but not super tight when i put them on (like perfect fit except for the waist) but after i wear tem for like and hour and they get huge on me and baggy and super loose. i dont know what to do they are all aeropostale brand and american eagle. jeans and capris. please what can i do to not make them get big... thank you!