Level 19, I was in the middle of the DLC Old World Blues. I needed around 50 - 100 more exp to level up, and just when I killed this robot dog it tells me that I've gained the Lord Death perk and then gives me around 200 exp. It shows the LEVEL UP sign and I hear the audio to it, but it doesn't show the level up screen to add points or unlock any perks. Also when viewing my pip boy my exp is 29641/29450, please help I am unable to level up to level 20

Nevermind, it fixed by itself LOL I decided to stop staring at the exp bar and started killing things and progressing just to do stuff knowing that I can always go back to the save and then it finally showed the level up thing minutes later

What usually happens is that something you should be in combat with is still hanging around somewhere, and it won't let you level up while you're in combat. I had something like that happen with a radscorpion that only the barest tip of its tail was above ground level. I couldn't level up, or wait, or any such thing until I either left entirely or killed the thing. I finally used grenades...