The symptoms you've described can be attributed to an anxiety disorder, hyperventaltion syndrome, or a combination of the two. Your doctor said hyperventalation and reached that diagnosis from his own criteria, and the information you gave him. Since I don't know his criteria or what you told him, I certainly don't have much leeway to disagree with him.
Hyperventalating is one of those extremely sneaky disorders because we can be doing it and not even know. That is, until the affects hit us like a ton of bricks. But, because we don't know we've been over-breathing, we don't know why we're suddenly feeling incredibly freaked out by all these bizzare symptoms. As our anxiety builds, we naturally continue to over-breath and one just exacerbates the other. Like a carousel running amok.
Being aware that you may have a hyperventalting issue will help in the long run. You say that you have days when you "START feeling weird symptoms." The instant you begin to feel any sort of weird symptom, you need to take stock of not only your breathing but your thoughts and feelings, your level of stress at that moment. If you can, get to a quiet place where you can be more or less alone. Learn how to breath properly, deeply from the diaphram, inhaling through your nose and holding it for 10 seconds, slowly exhaling to the count of 10. Google some Yogic breathing or places like the Mayo or Cleveland Clinics have good advice for breathing through a hyperventalation episode.
I used to have it very badly and what worked for me really good and very quickly was breathing into a small paper bag placed over both my nose and mouth. When we hyperventalate, we've completely thown our oxygen and carbon dioxide levels out of balance. By "re-breathing" into a paper bag, we exhale carbon dioxide, breathing it back in restores the balance, usually with less than 15 breaths.
If you become aware of your breathing, if you learn what your first symptoms of hyperventalating are, try some of these breathing techniques. If they don't stop the "attack," then you may be dealing with anxiety. In which case you'll need more than a paper bag.
You may need medication and therapy to figure out where your anxiety is coming from. Medication to control the nasty symptoms while you work through the therapy. Do keep in mind that if this is anxiety, medication alone will definitely make you feel better, but it won't fix the problem, it just masks the symptoms. But, I think we may be getting ahead of ourselves here.
Try the breathing for awhile. If it doesn't work, time for another chat with your doctor about options.
I wish you the best
Peace
Greenlydia