What Causes Dizziness Along With Nausea And Headache?

So, two questions....1) Quick episode where dizzy, nauseous and quick head pain. Only lasted a minute max. I am on blood pressure medicine (losartan HCTZ) which has been well controlled for the last 10 years. Should I be concerned about this? 2) Getting strange warm feelings in posterior occasionally. Almost like blood is rushing through a vein or something quickly. Again, only lasts for a few seconds but might happen repeatedly (say 10-12 times over an hour) and then not again for a week. Any concern?