A sick and plugged liver will give you symptoms of oxygen deprivation. I wish I could remember what it's called but I guess that is not the issue.
You should do a liver cleanse. My feelings of oxygen deprivation disappeared immediately with a very successful liver cleanse. Make sure you ARE taking parasite meds at the time or at least Green Black-Walnut . Liver Cleanses release the parasites from your bile ducts and they will invade your whole body if you don't kill them as they exit the liver.
You can also buy food grade hydrogen peroxide H202 and consume it orally by the instructions to relieve the symptoms. It worked really well for me but you must be very careful to follow the instructions for dilution and dosage.
You should also consider that you may be anemic and need to take some form of iron. But do these things in the order I provided them. Taking iron when your liver is plugged is not a good idea.