Is it a cardiac or pulmonary issue.

I'm a female, age 18 from Bangladesh and I have a long term medical condition, ie asthma. My pulse has always been higher, somewhere between 100 or above. Few months back, I was having asthma attack and it accelerated to 140bpm. Doing an ecg, I was diagnosed with sinus tachycardia.. I was on Ivabridine for few weeks to control my heart rate.. As I have begun to monitor my body more in depth, I would see my spO2 has now declined from 99 to 96 (after observing several weeks). Sometimes I feel like my heart is beating irregularly accompanied by mild pain. Lately, I've been suffering from shortness of breath, mild loss of balance and also numbness for few minutes in my legs or arms. and also I have been  suffering from dry nostrils and sore throat. My eyes has also become dry and I sometimes experience mild bleeding from nose.. Any diagnosis for this weird symptoms?