Hi, I hope you're well.
I'm 18 and I've had asthma ever since I was born. I have been in & out of hospital and it's taught me a lot about asthma haha!
Anyway, when you have a flu or cold it often does trigger your asthma making it more difficult to breathe. As you have been told you are asthmatic you should have a reliever (blue inhaler) and a preventer (brown inhaler).
Try and make sure your asthma is controlled by taking the preventer (brown inhaler) once your wake up in the morning and before you sleep in the evening. DO NOT take your reliever (blue inhaler) so much that you have to become dependant on it, if you do, your body will just get use to it and rely on you taking it. You don't want that because your asthma then will eventually become uncontrolled.
To answer your question, when I am having an asthma attack I would barely be able to speak. I wheez constantly and am in a lot of pain. A few techniques that I find helpful are breathing in for 10 seconds and then out again gently. I do this repeatedly whilst standing by an open window or outside if I can walk. Drinking water helps too but not fast you have to be gentle. I have been told to take 10 puffs of my reliever (blue inhaler) in case of emergencies like an asthma attack. I take 1 puff and then wait 30 seconds before I take another and so on. This procedure usually helps and calms my asthma down. If it does not work my mom calls an ambulance because I cannot help myself.
I hope this helps you in anyway :)
It's best to clean your surroundings too. Avoid things or places that are dusty (might trigger your asthma). Sadly, if you love animals, steer clear from furry ones like cats and dogs.