This is my last hope. People do a lot of growing during their teen years - it's usually a time for exploring who they are and what they want. Getting in a committed relationship so early may prevent that exploration. You've had a rough life and being neglected by family and forced to take care of yourself before you should have had to, probably adds to the feeling that you have been cheated of the time you needed to find yourself. In addition to all this, you may be depressed - not just down in the dumps, but there may be a physical reason for the depression.
Depression is very treatable.
Sometimes depression is a combination of things that happen to us and a chemical imbalance in the body which affects the brain. Often, people just need a little help until they get a grip on the emotional stuff. Treatment might consist of taking some medication and talking to a counselor. Depression doesn't mean you're crazy. Many people suffer from depression.