First, I'm so sorry you lost one of your twins. From what I've read it's my belief that you do have either gestational diabetes or some form of diabetes. The fact you have many moments throughout the day where you feel jittery, faint and feverish worries me. When you say feverish does that mean you have a fever or just feel like you do? How long has this been going on? As an EMT I would get a second opinion right away!! Being that you stated you blood sugar is low a lot of the time you could go into hypoglycemic shock, signs would be confusion, acting like or feeling like you're drunk, slurring words, it's very serious. Do you monitor your blood pressure? If it's within a range such as 100/60 or lower that's another cause for concern. The fact that your doctors said it's not a very common complaint would be a red flag for me, I'd think it would be a red flag for them and the fact that it's not makes me think you need to see someone else ASAP. I totally understand your fears about passing out and I'm not going to lie to you, it's possible. One thing you can do is buy some glucose tubes, you can find that at CVS or Walgreens, etc. Glucose is not going to hurt you or your baby but rather raise you blood sugar fast enough that you won't pass out, it's a good thing to have in the house, even in your purse. Do you own a glucose meter? If not you need to buy one, the test strips DO NOT come with it nor do the lancets needed to poke your finger to test your blood. There are ways to get free ones, if I can find a website I'll send it to you. Please go get some help, some help from doctors that will take your symptoms very seriously.
Keep up the food intake. Peanut butter and jelly sandwich's, all kinds of juice, protein such as chicken and steak, the iron in the steak is a benefit. Keep you blood sugar up as much as you can. If you have meter, test you blood sugar right before you eat and then an hour or two later. If the number is within a similair range you're body is rejecting the sugar for some reason. Healthy blood sugar levels range from 70 to 150, anything lower or higher is cause for concern, more so if it's lower than 70, such as 60 or 50, that would really worry me. If you're getting a reading of 70 one to two hours after eating, that's a problem. Sorry to be so blunt but your situation sounds serious and it needs to addressed. I wish you the very best of luck. Don't stress, just demand the help you need.
Blessed be.