Gizmo has been doing the same thing for the past MONTH!!! I finally gave up and let him sleep with me in bed. Since then he sleeps through the night and is much happier. Plus im happier since i can sleep. Gizmo would cry and I too live in an apartment complex. He is almost 9 months old so hes close in age to your furbaby.
If you dont want him to sleep in bed with you another thing that may work is putting his crate in the living room or bathroom where you can still hear him yet he cant see you. Gizmo gets upset when hes in the crate and can see me. Just an idea whatever you decide to do will be the right choice for your baby!! Good luck