Since you ve not said anything about chest tightness, pain, shortness of breath of an unusual degree and most of the symptoms you ve written have to do with dizziness and feelings of faintness when standing then, my best guess on this limited information is that you may be suffering from a viral illness and you need to likely eat more AND you definitely should be ingesting more water. Your symptoms are not suggestive of a cardiac problem or heart attack. Your blood pressure is dropping when you stand because you are likely volume depleted. Please tank up with good ole fresh water...no need for electrolytes or anything fancy....just water. Also, if you re not eating well these last couple of days try at least to get soft food, pudding, or chicken broth down the pipe. Of course, if your symptoms become worse or it becomes impossible for you to hold anything down then, I would suggest a visit to your closest ER. If this information has been helpful I d greatly appreciate your leaving a bit of written feedback and a STAR RATING. Also, if you d like to ask me more questions or strike up a private conversation with more information about your condition you can write me at: bit.ly/drdariushsaghafi All the best.