Profitability and profit are not one and the same thing. As a business owner, one should try to make every product or service stream profitable unless of course, you would need one stream to remain loss-making in order for another to help you make greater profits.
There are Key Performance Indicators (KPIs) that one could implement to see if you are running profitably. Broadly, Gross profit (GP) margin is one that most trades businesses do. However, it is also important that you do a Net profit (NP) margin. Net profit takes into consideration all overheads as well.
Depending on what your business is, you could drill down further to keep a tab on each of your expense overhead by building KPIs as you need and then keep a track of your numbers every month to ensure that you are not underperforming.