Don't forget, that the most likely reason you are low is that the numbers for where you "should" be are based on a population-wide average, not your personal baseline. (I, for instance, have naturally very low sodium levels. My baseline is usually just below "average.") If your appointment is not for another two weeks, then the doctors are not worried that this is harming you. When my sodium levels got too low, even for me, the phone call with my test results included instructions to go to the ER; my doctor had already filled out my admitting paperwork. When my iron levels were low, the phone call included instructions on the proper supplements, but they weren't low enough for my doc to be concerned enough to schedule a follow-up test.
Not only that, but every average for a general population has a degree of error. Your vitamin D is 10% low, for example, but for some people, 20 nanograms/microliter is adequate, for some people, their baseline is closer to 50 n/l, and a count of 20 requires treatment. Your overall health will be taken into consideration with all of this. You might get some good advice on how to keep your levels up - long-term deficiencies can cause problems - but it doesn't sound like your doctor is particularly worried.
Keep in mind, too, that on the internet, you can find a million things wrong with you. There will ALWAYS be something awful to match whatever symptom you have, whether physical bothering you, or the result of a blood test. To paraphrase an old medical analogy, your blood test was like the sound of hoofbeats. The problem is, you are now looking for zebras, when the most likely issue is a horse. In other words, think simple, not exotic. I agree with your assessment - right now, your biggest problem is you stressing yourself out.
Let us know when you hear, though. Sending well-wishes your way!