Depression is the worst mental condition of human being as the one who is suffering from it just looses his charm for life.
Now even if one is suffering from HIV or any other fatal desease u never loose that charm,and there is always a hope.On the other hand if one is depressed it implies no hope.
Now Bejasis I don,t know about ur exact situation as depression has certain levels and at the worst level ,the patient attempts or all the time thinks of sui cide. If this is the case I suggest u to consult a specialist on mental deseases and ask u to be always with someone,otherwise it will be too late.
If its just about lack of appetite and sleep then u can take some sleeping pills to relax urself,plus u should try jogging ,exercise or swimming.
SWIMMING ,I believe is the best for the one who is depressed as it teaches u how to fight for ur life and dont give up.Do it regularly .Dont eat things which generate heat in ur stomach.Eat a lot of fruit and dring a lot of juices.
Try to focus on all the positives u have,may be ur looks,qualification,love etc.
I don,t know if ur a muslim otherwise I would suggest u to offer prayers five times.
Anyways if u try these ,Im sure with the help of Allah almighty u will get cured of this brutal state.