Hello, Presence of the fever in general shows that very likely the person is going through an infection which can be viral or bacterial and can affect different systems on the body from throat, ears, lungs, tummy, urinary system, etc. The best way to find the cause of the infection is to have a visit with the doctor which will do a thorough examination and determine the cause of it. As for the blood pressure it generally might be high when we are not doing well or can be unrelated to it, it might be that you just have high blood pressure and to know what is happening you will need to have your blood pressure checked regularly for a while so the proper treatment is initiated. Low oxygen can happen in patients with severe infections like pneumonia or it may be due to chronic heart or lung problems. The thorough visit and possibly examinations will determine the cause of this as well. I hope I have answered to your query. Let me know if I can assist you further. Take care Regards, Antoneta Zotaj, General & Family Physician