Seratonin is responsible for the "obsessive compulsive" component of the brain...Thats why ssri meds work for ocd, anxiety and depression.
Do you have any other sympotms? Is it problematic? Do you do anything ritualisticaly to make the thoughts go away?
You may just be stressed out...But if youre worried go talk to a therapist or your doctor.

I just think I overthink alot and I get so annoyed by it have stjohns wart will give that a go thanks for the reply

When your at home your ok but at work you overthink.. Maybe you just need to change jobs.. Could be you need more of a challange .. Just a thought ..

When you start overthinking you have to do something to interrupt it - like clean your room or write a story - don't just sit there and think - I have done the same thing and next thin g you know an hour has gone by. Play the guitar - make a list of things you have to do and when you start thinking too much look at your list and do something on it.

I think its better to see a therapist first.

I'm getting really pissed off at this whole believe that depression and anxiety is nothing more than an easily treatable chemical imbalance. There are countless stories of people who have tried drug after drug after drug without success; and that's probably because they are failing to address the reason their chemicals are out of balance in the first place... Often its childhood issues that need to be resolved.

Medication ssris specifically can be helpful in the short term for some, but I think therapy is going to do a better job of getting to the root cause. We have drug solutions for everything now and i'm just not buying the whole chemical imbalance argument. Its in our lifestyles, in our events, how we percieve the world. If it were just chemical imbalances every country would exhibit the same amounts of depression and anxiety, which is simply not the case. Culture and personal events and individual perceptions of the world are probably the key reasons for the chemical imbalances.

I kind've believe what robotman is saying. I do believe in chemical imbalances. But also believe in the childhood issues. I've been thru it all. I live in a small town, one counselor, I came out of there after an hour with 5 disorders! Lol. 3 of them that I didn't even know I had. Imagine if he heard my whole life story! I would be locked up somewhere. I worry excessively about little things, then when big things actually happen, I fall apart. I"m on lexapro now. I've been waiting four months now on an appt. With a phyciatrist! Just hang in there. I do think alot of how you percieve things come from childhood issues. If you're going to go to therapy, find a good one! I also have ocd, had it for years. Sometimes I have to laugh at myself. Laughter is very good medicine!