Past 5 months i've been having random memories n childhood memories, is it normal to be randomly so nostalgic?

What is the trigger?: I would recommend you see a psychologist to see if there is any psychological trigger for this. If, by nostalgic, you mean sad, or depressed, then it is not normal. Have a physical exam, see a psychologist, and if warranted he or she will refer you to a psychiatrist if needed. Perhaps you are missing something in your life that you enjoyed in your childhood. Whatever it is, a psych will help.