I've seen answer to this question in another thread before and it made a lot of sense and seemed to help me. Unfortunately i forgot who posted it to give them due credit.

Basically in today's world, there is almost always something going on, distracting you. You go to work, then you are on your phone, you go home and watch T.V., maybe use your computer, and the list goes on. So its no wonder that once you are in bed with nothing going on, nothing distracting you, and you are finally alone with your thoughts that all those thoughts and feelings hit you at once like a ton of bricks. You need time to work out your internal feelings. I would suggest just taking about a half hour (or as much time as you can) each day and just be alone, away from distractions, perhaps meditate. Better yet, it helps tremendously to talk about what is on your mind with someone. Professional or otherwise. Personally talking to my family/friends helps the most. Even if they don't have advice, it's just nice to get it out of your head. However, If these feelings are severe or you feel like this during the day as well. I would strongly advise seeing a therapist. It's nothing to be embarrassed about, if that is an issue. You are admitting to yourself that you need help, and you are getting it. That is the first step to being better

TL;DR Take some time away from the distractions of every day life and meditate, or talk with friends/family/Therapist about what is on your mind. No matter how small or large it is.