Am I having panic attack (time sensitive)?

I know this is stupid to ask a health question here instead of going to the doctor, but I don’t have much time now.

I have to sit for an exam shortly. Yesterday while I was perparing for a noon nap my heart beat fast all of a sudden. I also had an anxious feeling, like something bad was going to happen and I couldn’t rest. It lasted until my noon nap was over, for about an hour.

I thought it was over but then it came back again while I was reviewing things last night. This time it lasted much longer, for about 4 hours.

This morning as soon as I woke up it came back again, this time it was even accompanied by the lost of appetite and a light headache. I have tried everything from breathing deeply to distract myself for a while without success.

What is happening to me? Is this a panic attack or something else? I really have to get out of this mess so that I can take the exam.