I thought about this one for a while. Most likely you are just fighting a virus. Give it time. However there are other possibilities.
Humidity is one effect from a tank in the bedroom. Most of the time your body likes humidity as there is less drying of mucous membranes. However excessive humidity can increase growth of molds in your bedroom to which you might be allergic.
Other substances in the tank can also cause a problem. However most of these would not be aerosolized (become airborne) in a saltwater tank from evaporation. However if you have a protein skimmer, the amount of material could become noticable. The one I would think is most likely would be Iodine. If you were allergic (you probably couldn't eat shellfish without your mouth swelling up) the small amounts of iodine could make your throat sore (especially if you supplement in a reef tank). In addition the material that the skimmer removes (e.g cyanobacteria (red green algae) which has been known to cause disease in humans) could also be causing problems.
These possibilities are stretching a little. Gargling with saltwater (not from your tank
) before you go to sleep might help.
