If that five-month job was relevant to what you were doing now, and you left for a good reason, rather than that you couldn’t hack it and you had to get out of there, then you should definitely include it.
Also, keep in mind that some employers require that your job history be complete and that you account for every single job you have ever held. You can be disqualified permanently, if you leave something off your job history.
Even if it is awkward and uncomfortable, you should include that job. Leaving it out may be more costly to you than including it.