Many here have had mood issues and ones though patterns can go there when T deficient and those thought patterns become a rut and one can get stuck there. Many other things can contribute such as thyroid/iodine issues, stress, cortisol/Adrenal_Fatigue etc. As Phillip states very articulately, all of this is tied into ones love life and other social factors; and that is also affected by ones mood history and hormone and other health issues.
Stress can wear you down and been in a dark/moody space is stressful as well, creating a trap.
I suggest tackling the easy health issues first, if you can get motivated to do that. Thinks that do not involve drugs such as iodine status, diet/supplements and sleep hygiene should be tried first. If one needs thyroid meds, then they can make a big difference. One might need cortisol and hopefully that is not needed later after other issues are resolved.
Then you can try been pharmaceutically assisted. If you simply feel dull and find little pleasure in anything, including good food, you probably need an boost in dopamine. Wellbutrin would be a good first try and it avoids the nasty problems that all SSRI's have. If you have panic attacks, a small amount of an anti-anxiety med can make a wall of pain slide away. You would want to limit the duration of that to as little as possible as the effects can deepen some aspects of an underlying depression.
Wellbutrin is also a bit stimulating and that can be useful. If that interferes with sleep, adjust timing of doses to earlier in the day. Some need melatonin to get to sleep. That should be time release to avoid wakefulness later after the half-life. I find that trazodone is very good for sleep and when dosed right, it does not have drowsy drag-over the next morning.
There has been a large shift in focus here, at least by be, concerning thyroid function and iodine deficiency. You can check your overall thyroid function by checking your body temperature WHEN you first wake up AND mid-afternoon. See the thyroid basics sticky for more on body temperatures. You also need to have had a steady identifiable source of iodine for years in your diet, from iodized salt and/or vitamins that list iodine. As selenium deficiencies are a serious risk factor for thyroid autoimmune diseases, make sure your multi-vits list that as well.
You can also list your lab work with ranges and other details as per the advice for new guys sticky.