Your thoughts send a signal to your body to release a certain set of chemicals which causes you to feel a certain way. We call this our emotions.

Our emotions then send a signal to the brain which confirms the thought that we just had, which causes us to think more similar thoughts. This lets the body know to release more of the same hormones which increases the feeling.

Now we are in a thought-feeling loop. We call this a state of mind. Our thoughts are triggering our body to feel and our body is triggering our mind to think.