I agree with madjp you should see a doctor as soon as possible.. The fact nitro (dilates coronary vessels) provides relief to your symptoms almost always indicates a lack of blood/oxygen to heart cells usually due to constrcted vessels (vasospasm) and/or partially occluded vessels..
The danger is ischemia (lack of blood flow) doesn't always result in chest pain or any other symptoms. When there is ischemia there is a probability of heart cell damage and a silent heart attack. My first symptom of a heart problem was congested heart failure caused by ischemia and damaged heart cells.
APO-diltiaz belongs to a family of medications known as calcium channel blockers. It is used to treat high blood pressure and angina (chest pain). It works by relaxing blood vessels and by reducing the workload of the heart. .
There may be an interaction between nitroglycerin medications (dilates vessels) and any of the following (e.g., vasodilators, calcium channel blockers, ACE inhibitors, beta-blockers, diuretics). If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to stop taking one of the medications, change one of the medications to another, change how you are taking one or both of the medications, or leave everything as is.
Speak to your doctor or at the very least to your pharmacist.
My two cents: January is way too long. Find another Dr. or ask if you can sit in the office one day as a stand by (you could also just show up and tell them you want to stand by and then do it regardless of what they say) - that often works. You might want to taper off the exertion as well until you've been seen. Best of luck.