My first Invisalign tray feels very loose but my second tray is not even close to fitting, yet it has been 13 days. Advice?

there is saliva getting caught under the tray which is causing me to have to make a "sucking" sound many times throughout the day ( it's driving me nuts. Not to mention it's embarassing. this is how I know the tray is loose but i cannot fit the second tray on yet. I feel absolutely not pressure on my teeth anymore.