This sounds very much diet related and to lack of exercise. Also, you should not be taking calcium supplements if you have constipation problems. This can make constipation worse as it helps your bowel to absorb water back. If you are constipated then try taking some Magnesium instead.
Basically, your GI system needs fiber to function effectively, so you need to start Metamucil. This is a water soluble fiber supplement and is safe to be taken twice daily, but ensure that you drink at least 6-8 glasses of water with it.
You need to include more fiber in your diet and eat more carbs, fresh fruit and veg and you should also be drinking at least 2-3 litres of water daily to flush your system through. Prune juice is very good for constipation also. You also need to develop healthy eating strategies, so that you are not on a starvation diet. This is no good for health at all, can easily make you constipated and more than that, if you don't eat you have no energy to do anything such as exercise. You just have to try and develop sensible strategies. Your GI system was designed to eat food and for fiber and without this it will not function properly.
Take plenty of exercise too. This will increase gut motility and help things through your system easily. I also cannot reiterate enough how important it is to drink enough water. If your body it too dry, then you will get constipated.
If you are desperate, then it would be ok to use a suppository to help stimulate your bowel. The fact that you have no desire to open your bowels probably means that you are backed up inside and the fact that you have been constipated for so long will not resolve overnight unfortunately. You need to be patient. It is also ok to use a stool softener for a little while such as Sodium docusate.
Hope this helps?