First question is, why antibiotics? Did they diagnose anything that would require this? Taking antibiotics creates problems with your digestive and immune systems, as well as mental health in some cases as it kills of beneficial organisms that help with these things. Giving an antibiotic without reason is how we got into a mess with them, and so I would again wonder, did they find something that led them to do that? If so, what was the issue they were attacking, as it might have something to do with what's going on, and if it was just docs throwing drugs at you, that's not a great idea. A possible problem is one that some people who are on shift work as you are have, which is their circadian rhythms get thrown off and they end up really tired. Melatonin can help with this, but in your case you seem to be sleeping fine and sleep is what is usually thrown off, but the quality of your sleep may not be what you need because of a sensitivity to shift work. So there's one possibility. It's a hard one to treat, however, as the way to see if that's the cause would probably mean stopping shift work and see if that fixes things. Which means you're out of a job, so not a great thing to contemplate, but the possibility is there. Some of what you describe could be caused by hormonal problems, which could be an imbalance of sexual hormones or a thyroid problem. Testing for a thyroid problem requires testing docs don't do unless you specifically tell them to do it, as the usual blood test really tests your adrenal glands, which are intimately connected to thyroid function but you have to figure out which part is off to fix. As to getting depressed sometimes, do you mean feeling down or sad sometimes or depressed? Not the same thing -- one is a disorder and the other is the normal fluctuations of life. There are emotional possibilities -- you hate your job, you hate working alone, the shift work interferes with your social life, etc. Can't tell you what it is, but there are so many possibilities that the average exam with a doc don't go deep enough into to discover, not only the above but also blood sugar problems, nutritional deficiencies (you don't discuss you diet), lack of exercise, etc. To dig deeper you might need a better doc or a deeper interaction with your current one, and need to look at you lifestyle and see what's in there that might be bugging you physically and mentally. You could also have a sleep disorder, such as apnea. Just a lot to get into. Keep searching, and if your current doc doesn't seem to be doing the right things, find a different doc, but also look at natural medicine topics, such as exercise, diet, and the like.