I've lost 10 pounds in just 5 days and i'm not on a diet or anything, i've mood swings/depression and don't sleep, could this be related to weight loss?

Possibly: Or a mood disorder could be related to decreased appetite. Much of rapid weight loss is due to fluid. Please seek prompt medical care for the lack of sleep, mood swings & weight loss.

Could be: Beginning of anorexia nervosa, a dangerous disease so you should seek help locally.

Same body, right?: A connection is likely, but what's more important is they all sound serious. It would be wise to see a doctor asap. Also, find a therapist/psychologist who feels right for you. All of these concerns deserve attention now. Till your therapy gets going, make sure you keep hydrated, think about supplements, and eat whatever you can. Be well!

Yes, or more serious: The presence of mood swings, and a lack of sleep are common symptoms of some psychiatric disorders, specifically: major depression, bipolar disorder. Do you stay up 2 or more days without sleeping? Have you been so excited that sometimes no one understands you because you talk so fast? If you answer yes, then you should see a psychologist or psychiatrist to get assessed for bipolar disorder.

How is your apetite: Mood swings and anxiety may cause weight loss. Or weight gain for different people. If depressed mood causes you to eat less and remain restless or have psychomotor agitation you will lose weight.

Too much too fast: Losing 10 pounds in 5 days is too much, too fast. With mood swings and lack of sleep, you could be having a hypomanic or manic episode with hyperactivity. I've also seen people in a thyroid storm like in graves' disease lose weight this quickly. Please see your doctor asap!

You can't lose: True weight that fast. 10 pounds in 5 days would mean burning off 7, 000 calories a day that you don't eat. That would be the equivalent of not eating much and running 70 miles a day, each day. Either the scale is inaccurate and/or you've had a shift in fluid. Try a different scale. If it continues to decline, which is doubtful, see your doctor.