If blood pressure is low, then you could feel weak or dizzy while standing. I don't know about
elevated blood pressure. A lot of times my blood pressure is elevated when I'm in the doctor's office even though I take medication for blood pressure. And because of that, I bought a blood pressure cuff at a local pharmacy and I test at home. It's always normal and sometimes on the low-normal side here.
The next time (and every time) you have any lab tests, ask them to give you hard copies of the results. They may have to mail them to you. This is your right as a patient. This is for your records so you are not in the dark about
what your test results are. You will also feel more "in control" or things by knowing lab results.
Instant oatmeal normally makes blood sugar spike and then drop. When it drops, you would feel tired.
Anxiety does have several physical effects on us, so when we do have certain physical symptoms or odd feelings that we can't exactly put our finger on, doctors normally order lab tests to see if we have issues with blood sugar or other things going on. I went through lots of tests many years ago, even a Holter monitor for the heart, etc. When all the tests were ok, it came down to anxiety. So, if they can't find any physical reasons, I think doctors will address anxiety and then the road to healing begins.