Meera, the two replies above cover the most common causes, and in our experience they usually appear together.
A diagnostic worth doing this week. Take your last thirty orders, and for each one write the price, your true cost including wastage, and the honest number of hours from enquiry to handover. Then calculate profit per hour, not profit per order. Almost everyone who does this for the first time discovers that their most popular product is their worst one, and that a small number of high-touch customers are consuming a disproportionate share of their week.
The fixes usually follow directly: retire or reprice the loss-making line, standardise designs with priced customisation as Vikram describes, and put a minimum order value on the things that only make sense at volume.
One more thing worth naming, because it is doing real damage: you said you are turning down work while being broke. That is a strong signal your capacity is being spent on the wrong orders rather than that you need more of them. More volume will not fix this — it will accelerate the burnout.
This is squarely what the business strategy portion of our programme exists for, but you do not need a course to run the thirty-order analysis. Do that first.