Rule number one in sales : never stop to sell

What you can do is to reduce your ad spends and provide a pre-order button directly on your product page. This pre-order option will inform your customers is not available currently and then can be notified when it will be again by giving you their email.

I am in the same situation as you. Everything works fine but I don’t found the motivation to do more. So now I try to spend my energy in some side project/business.