Definitely go back to the doctor. This is not normal.
Many people do get benign 'ectopic' beats, extra beats which can make people feel flutterings in their chest. This can last for a while and the more anxious people get about it generally, the worse it gets.
However, the definition of benign is not causing any pathological signs, and self limiting. You are experiencing symptoms highly suggestive of a cardiac problem, chest pain
, breathlessness and dizziness
being the key ones.
Id request an ECG, an exercise tolerance test and an echocardiogram
of the heart to look for valvular or septal defects. Sorry this is UK terminology.