I've heard that depression, stress, ect. can take a toll on your physical health. in what ways?

You heard right!: Each of those feelings set into action a whole long sequence of biochemical events that have impacts on many bodily organ systems. If they happen frequently for years and years, yes - it certainly takes a toll. You are wise to think about this and to take steps to resolve issues in your life that bring about depression and stress, etc. Take care!