I'm curious about the safety of Hydro oxygen Plus that you are using. There are a lot of variations in the market. Here is a site that has familiar side affects that you have been experiencing.
This is an Oxygen Therapy Forum. One Oxygen Food site said to be careful, that some are not safe. I am experimenting with CoQ10, which I really like because it helps my bad breathing.I heard on the radio yesterday about a product that has CoQ10, flaxseed oil, salmon oil and Gingko Boloba, by Purity brand but I forgot the name of the product.
Here is an Oxygen product that is worth looking into:
www.goodforyou.ca