Is it depression or something else?

Dear Ask The Doctor: Hi there, For a long time now I've been sure there has been something wrong with me but I've never been quite sure what, as the symptoms I get seem to be linked to so many things. At the moment I've kind of just settled on depression, as I'm pretty sure I had an episode of depression about 10 years ago, but never got any medical diagnosis. Ever since then I've become a lot more sensitive, as in it doesn't take a lot to upset me. I also have a lot of other common symptoms of depression such as fatigue, loss of concentration, loss of social contact and activities that I used to enjoy doing...But along with these, I also have some more. I don't get sunburned often as I'm pretty careful about it, but I'm really really pale. I know some people just generally have a lighter skin tone, but my skin colour just seems different, like more yellowy or something. I also get cold really easily, even when everyone else is taking clothes off from the heat. In the summer I'm still usually wearing long sleeved shirts and trousers so I don't get cold. Tiredness is a big thing also. I don't have the best sleeping patterns, but even when I'm going to bed early and get a good nights sleep (8-10 hours) I still wake up and feel absolutely whacked. I have problems with concentration, sometimes forget little things and I have no motivation. Another thing is my appetite. I eat when I'm hungry, but sometimes I just don't get hungry. I can go a whole day without eating, and still not feel hungry. Even when I am hungry and eat a meal, I only eat a quarter of what most of the people I know eat. I don't think I'm underweight, and if I am, it's not drastically underweight, but I still look really skinny and bony which I'm thinking could be because of something like no muscle tone. Anyway, I've never really gone searching for any help because it just seems so easy to put it down to other things, like being tired because I didn't go to bed early enough. But I think it's all starting to impact my life much more than I'd like and I just want to be normal and get things back on track. It'd be nice to know if this could be mental health related or something else entirely, so I have more of an idea of where to go from here. Thanks.

Dear JJ: One of the conditions that closely mimics depression is hypothyroidism (underactive thyroid). Symptoms of depression include depressed mood, sleep disturbances (increased or decreased sleep), loss of interest in activities that are usually pleasurable (sex, hobbies), low energy, poor appetite, no motivation, suicidal ideation, etc. However, hypothyroidism presents with very similar symptoms too; I am more inclined to infer you have hypothyroidism because you have cold intolerance (feels cold in a warm room). Other telling signs of hypothyroidism are weight gain with no changes or increase in appetite, anemia (which is probably why you’re having pale, slightly yellowish skin), low heart rate, muscle pains, etc. Some hormonal problems can present with similar symptoms as well and blood tests are needed to diagnose this. I strongly suggest you see your doctor as soon as possible so a physical exam, blood tests and other procedures can be done. I do hope I have answered your question and take care always.