Drugs to treat high blood pressure can cause fever in the afternoon. The nausea may be from being off balance due to the blood pressure too. It may also be due to blood sugar if it is off. Once they stabilize your bp I wouldn't doubt that you see your temperature go down. If it doesn't then talk to your doctor. But I think the BP is what is causing the temperature in the afternoon.
take care,
mkh9
Any other symptoms? Do you live in an area that is has a malaria risk?
Were your meds increased before you started getting sick? It could possibly be that the medication is affecting your blood sugar levels. I was recently dx as pre diabetic and put on Metformin. I noticed I would run a low fever, be severely nauseous and dizzy after taking my meds. I never knew that the Metformin could cause it. I stopped and now I am fine it cleared up within days of me stopping the metformin. I am not saying to stop your meds and see but check the patient info sheet to see if it can affect your blood sugar or call your drs office and talk with a nurse to find out. Best wishes, Sissie