Do You Experience Tachycardia and Shortness of Breath During Postdrome?

I have been diagnosed with chronic migraine and often feel weak and exhausted for a while after the migraine. It has become difficult to know when what I am experiencing is part of the migraine attack. Up until very recently, I have had about 5/7 days a week that I have felt impacted by migraine - and I don't necessarily feel "normal" on the other two days. It seems that when I have a particularly bad migraine, I have lingering feelings of "weakness" by which I mean I get a rapid heartbeat accompanied by shortness of breath with very minor exertion. I do not think there is anything wrong with my heart - I just had a bad visit with a cardiologist, so please don't suggest that! When most of my other symptoms have lifted, it is hard to tell if this is still migraine postdrome. I just started Emgality a few weeks ago. It may be sort of helping - I get symptoms but they are more fleeting. This is good, of course, but it also leaves me unsure as to whether the symptoms are mild migraine or something else. This is confusing - but I am hoping that it will become more clear after I have been on the medication longer. Thanks for reading and I appreciate any input.