The point to bear in mind while doing workouts is that it is not important to complete the workout in one go. If you cannot keep it up for a full 30 minutes for any reason, you can continue at a later point of time. Exercise done in small batches is going to yield similar benefits as a lot of exercise done at one time.
But whether you do it in small doses, or you do it in one go, you must keep up your efforts. A regular workout session is a lot better than one not done at all. It is also a lot better than exercises done irregularly. So, it does not matter if you can do only small amounts of workouts daily. The important point is that it must be regularly done.
It is a good idea to keep track of all the changes in your body during and after you workout. This can be done efficiently using gadgets that monitor heart-rate or the pulse.
You can strap it across your chest, and it is going to be easy to know your heart-rate while you are on the run or are jogging. You are sure to get an instant feedback this way.
This way, you are going to be armed with a lot of data relevant to your physical health when you walk into your physician's for a consultation. The data is going to help him a lot in forming the correct opinion of your overall health. This is also going to give you some confidence that you have made some progress in your efforts.