If you’re crazy busy all of the time, not just at peak periods, then it is probably because your prices are too low. You can either increase prices to make fewer but more profitable sales or you can raise your prices enough to increase your workforce.
The other way to know that your prices are too low is if nobody ever says “no”. If everybody you quote says yes, or if nobody bounces when they see your prices on your website, then you probably have scope to increase them.