Suddenly felt uncomfortable and dizzy, heartbeat was fast and i got sweaty and felt weak. this attack lasted few minutes and i felt anxious afterwards, but otherwise normal. what could this be?

Onset of flu or common cold or COVID or dehydration or food poisoning to mention a few. Need more details. Keep a diary and share with your Drs. Your body is talking to you. Take notes and share and you all will figure it out.

Your symptoms, if recurrent could also be due to paroxysmal tachycardia. If frequent, such events could be detected using a heart rhythm monitor. Your doctor will be able to help you further. Please try to count your pulse if the episode recurs so that you are able to give your doctor adequate details. The vast majority of these are benign. Avoidance of alcohol, recreational drugs etc is a must.