This popping and cracking sound that you are describing from your toe are unlikely to represent too little calcium, but they may be a sign that there is some chronic problem with the ligaments or tendons that insert on that toe. Over time, all of that popping can lead to inflammation that eventually causes irreversible changes in the muscles or there attachments, and there can be arthritic changes. It should be evaluated by your primary care doctor
, who may or may not recommend another visit to a specialist who may choose to either get a radiographic image, place a small splint, or, most likely, continue to observe the area. He or she may recommend some special exercises that you can do to reduce strain on that toe, and may suggest strengthening maneuvers or even special orthotics to protect the area, all of this depending on what is obvious when they visit with you. As with any doctor visit, the key will be in how long this has been going on for, when it started, if there was any extra trauma, and whether things have been getting better or worse. Please discuss these with your doctor, and follow their recommendations for improved foot health.