You say you think you're suffering from anxiety, but it's really easy to know if you are or not. While there are many physiological symptoms that might be associated with suffering from anxiety and depression, both disorders are characterized by thoughts. If you're chronically thinking anxious, irrationally fearful thoughts you're an anxiety sufferer. If you're not, you're not. You don't say what's going on in your mind, and that's the most important thing to tell both us and anyone you see for treatment to know. Being tired and feeling like you're going to faint are physiological in nature, and only if they come on because of anxious or depressed thinking are they a mental disorder. They are also, by the way, side effects of taking antidepressants like Celexa. People vary quite a bit in the side effects they get from taking meds, but those are two of them. You don't say if you were feeling like this before starting the medication. Here's the thing that happens with so many particularly Americans -- you go to the doc, complain of something, the doc can't easily find something wrong, and attributes it to anxiety because you say you're feeling nervous. But everyone feels nervous when they don't feel well, at least to some extent. Don't believe your doctor is good at what he or she does just because of a degree -- as with everyone else, some doctors are great, some are mediocre, some are awful and chose the wrong profession. Some are just lazy or overworked and take shortcuts, which usually means meds you might not need. So, tell us about your thinking, and how it's affecting what you do in life, such as avoiding things because you're frightened even though it's something you've done a lot and were never frightened before. That's an anxiety disorder, and you may well have one, but from what you've posted so far, no way to tell. Now, let me just list a few things that can cause symptoms that mimic anxiety and depression or cause it: nutrient deficiencies, lack of proper hydration, poor eating habits, sleep disorders, thyroid problems (which doctors are horrid at finding), hidden viruses and bacterial infections, blood sugar and hormonal imbalances -- and that's just off the top of my head and I'm not a doctor of any kind. So again, what was going on in your head that got you put on Celexa in the first place and we can be of more help.
Which meds? Sometimes you have to try a bunch before you find one that works for you. Have you tried therapy?