You are so far away from being alone in this issue, I'd assume most people came to this site initially because they feel sexually inadequate in SOME way, big or small, lasting long or not, I think most guys are self conscious about their size. The good part is you can increase your size with patience and consistency, but for the record I'm the only one I know in person that has a girth of over 5 inches, I've searched the average to be 4.7.

As far as length there is nothing wrong with it, but if you want to focus on that then I've been doing 1 minute of stretching (straight, up, down, left, right) so total of 5 minutes, and then just regular jelqing (started at 50 a session and now I'm at 4-500 a session but might be overdoing it)...anyways I've noticed good length gains that way so maybe try it out.

Try not to think negatively about yourself, you have nothing to worry about at your current size and guys put much more self-worth into penis size than women do.