I'm quite the opposite right now, having returned to airsoft after a good number of years I feel refreshed and ready to shoot shit! However, I can completely acknowledge what it feels like to burn out on airsoft.
I simply had other interests that I wanted to sink money into. For me it was cars, motorsport and trackdays. I think it's one of the few things that rivals airsoft in cost! ?
As others have said - maybe it's time to refresh and minimise your kit back to basics. Or, like what I did, sell off the majority and keep the basics - knowing you'll be back at some point in time.