Good Morning Alok and welcome to our forums.
With a mechanical valve in the aortic position the recommendation is an INR range of 2.5 to 3.5. Most people can keep it within those limits by eating a consistent diet and watching their vitamin K intake.
Bleeding should not be an issue for you. Most all of us are constantly getting cut or scraped and we just bleed a little longer then usual but nothing serious.
You say your depressed. What is making you depressed? If it's really bothering you, you might want to talk to your Doctor and get some anti-depressant therapy started. It's very common to have the feelings that you have, so don't be afraid to say anything about it. We have all been there and through it.
May I also suggest that you look into another member of ours, Mr. Al Lodwick, who is a certified Anti Coagulant expert, runs his own Coumadin Clinic, as well as maintain his own website. The man is a wealth of information concerning the drug and it's usage. I would highly recommend giving his site a look. You can see it at :
http://www.warfarinfo.com/
Tons of questions can be answered at the link below
http://www.warfarinfo.com/warfarinfo.com2.htm
He comes on here in the Coumadin forum and answers questions and concerns also, should you need to speak with him on a subject.
Again, welcome. I hope you enjoy yourself here and learn as much as you possibly can about the information you seek. The anwsers are here.