I have asthma symptoms from dust mites, and discovered that sniffing items creates a reaction in my lungs that is pretty sensitive to the amount of allergen in the item. Dust mite allergens also have a distinct but subtle smell you can learn.
Regarding whether or not your health issues are caused by dust mites, if you have any of the allergic disease, or if you have a tested dust mite allergy, it is likely they are causing problems. Disease severity is also associated with dust mite exposure.
Basically, the worse you have allergies, the more likely it's dust mites.
It's an almost certainty you home has dust mites and their allergens, unless you live in a very dry climate.
My advice is to create conditions in your house in which dust mites cannot thrive, which is relatively easy to verify with hygrometers. Over time, this will lead to lead to lower allergen levels, particularly if you are proactive about removing the ones that are currently there.