If you are constantly feeling dizzy, or go through fainting spells, please have it checked out by a physician. This is not normal and needs to be evaluated.
Remember, a stitch in time saves nine.

When you visit the doctor, ensure you discuss the list of medication you have been prescribed, and be truthful about what you consistently consume.
Do not make the mistake of measuring your diet by what groceries you purchase, instead use the yardstick of measuring it based on the food that you choose to put in your mouth.
Learn the difference between filling your stomach and eating a balanced meal.
Those who take antibiotics and painkillers need to consume more healthy foods to be able to help our body process and assimilate the medication. Include this when you plan for your meals while on medication.
Keep a log of the symptoms you feel and observe while on medication, it would be easier to discuss it with your physician periodically. A medicine that has worked well for you for years together might have side effects over long term.
Stay hydrated. Stay healthy.