Weird shortness of breath after excercise

In the past month or so I have noticed a shortness of breath like its hard to breath in a bit, quite annoying. And usual high heart rate. I find myself taking rather deep breaths & it feels i have to manually breath rather than it just coming naturally. It usually happens after exercise which ive been doing everyday for several months now. I'm pretty fit & my usual workout while long is easy as I have learned to pace my self. But latley i cant do my usual workout without needing small breaks in between as my heart rate eventually gets too high, But previously I could pace my self & last the workout. I think maybe small variables like cold weather kicking in & humidity & air. Sometimes i get wheezy & cough to clear my throat of Flem which helps alot. But soon after my air ways don't feel right & im shortness of breath. I noticed drinking small sips of water or drink helps the feeling in my throat & makes it feel a little easier but only for a small time. Id feel better if it was just asthma being sparked by workout or being low on certain vitamins or something.