There is nothing abnormal about the feelings you are describing. You have learnt not to value yourself or your needs because the message you received as a child is that you were a burden. You now have to learn to value yourself and see that other people value you too. It's a process and you are doing great
For what it's worth, "forgettable' is the last word I would think of to describe you. Your posts on PC are invariably wise, thoughtful, caring and intelligent. I was really surprised when you said your age on another thread, as you are so damn insightful- beyond your years! You are a valuable and valued member of this, an anonymous online forum, so I can only hope that people who know you in real life know how lucky they are!