Unstable mental health.

My mental health is extremely unstable.
I have a mental health helper at work but as i have had a falling out with in the past I now feel very uncomfortable sharing my feelings with.
I know that I should try other mental health groups online but I am unsure where most of my issues start.
Most of the time I am upbeat and positive with my outlook on life but when I start to look at the reality of my situation I feel rather depressed and stressed out. I am unsure if I need to go onto medication or just stop over thinking situations.