Well..firstly I will say that owning your own business is one of the hardest things that anyone can do! I am not surprised that u feel that u can't sleep ..because work doesn't finish at the end of the day..your mind is still on overtime when u come home...so many things to think about. Also, feelings of tiredness and laziness is definitely coz of work too. However, in my opinion..u r experiencing depression for definite. I feel lazy, tired..sometimes can't sleep, withdrawn from people. All these are symptoms. I am no doctor so I can't tell you how depressed you are.
I know there have been many bad experiences of anti-depressants..however..the most successful one (which I take)..is Citalopram..(there's another name but I can't remember exactly the spelling celexa..or something
). They don't work for at least over 2 weeks...I am very impatient because I want everything to work NOW, so I understand your reasons for not wanting to take them.
If you feel like this depression is affecting your work and life in general (which it seems to)..then try some sor of medication..but u have to give it a chance (they say). I am still waiting for it to work, but if the people say it work...then it works!