First of all, congratulations on starting to exercise regularly! This is a very important step towards a healthier lifestyle. Maintaining a healthy weight and regular aerobic exercise will help to prevent heart disease and other medical problems later in life.
If you are having symptoms of exhaustion with exercise, i would recommend that you go to see your primary care doctor
. Although sometimes feeling exhausted can just be a sign that you are exercising to hard and need to slow down, it may occasionally be a symptom of a medical problem, like a heart problem. Your doctor will be able to perform a complete physical exam and make certain that there is nothing serious going on.
Assuming this exam checks out, you should be ok to continue exercising at a slightly lower intensity. On the other hand, if your doctor finds something concerning on the exam, they will likely want to do some additional testing, and they will advise you to hold off on exercising until those tests are finished.
Start by setting up a visit with your primary care doctor right away, and good luck!