TeenHealthFX is concerned about you. Although we cannot diagnose the cause of your racing heartbeat and dizzy spells over the internet, we can tell you that it sure sounds like you are not taking proper care of your body. We are glad that you recognize that your stressful lifestyle and poor eating habits may be unhealthy for you - now you need to take a step further and do something about it.
There are many vegetarians who maintain a healthy balance of the vitamins and nutrients a body needs to function properly. But being a healthy vegetarian takes some doing and is not as easy as simply eliminating meat from your diet. If you do want to continue with a vegetarian diet, TeenHealthFX recommends that you meet with a nutritionist in order to ensure that you are not eliminating any key compounds your growing body needs. Remember - adolescence is crucial growth period. It is perhaps even more important for people your age to maintain a well balanced diet so that your body can grow and develop as it needs to.
You also mention that you are under stress. Just like not eating properly can be damaging to your health, so can leading an unduly stressful lifestyle. We all have some degree of stress in our lives - the trick is not necessarily to try to eliminate it altogether, but to pare down your commitment so that you have a balanced schedule, giving your mind and body some time to rest and relax.
Again, TeenHealthFX cannot diagnose you here, but it is clear that your body is trying to tell you something. Irregular heart beats and dizzy spells are serious symptoms that should be addressed by a doctor who can properly evaluate the situation, diagnose you, and come up with a course of treatment. If you would like to meet with a doctor at the Adolescent/Young Adult Center for Health in Morristown, New Jersey, you can call 973.971.6475 for an appointment. If you don not live in the area, try calling your local teen health center for an appointment.