Won't be put down

My 8mo will not let me put him down the past week and screams bloody murder if I go out of his sight and tries to climb onto my lap if i even try to play with him on the floor. I'm trying to just go with the flow and have him in the sling as much as possible but I also have a 2.5 yo and am mostly with both solo so it isn't working and I can't take the constant screaming when I inevitably have to put him down sonetimes. Help!