So, I've made it to Arx, and then realized I'm supposed to have 3 max source points. I have 2. Is there any way to get the third one now?

It seems like a very strange game design to allow me to advance to a higher zone without telling me I'm missing vital quests, or warning me that I haven't completed an important step. I'm new to this game series, and I don't like to be constantly googling things while I'm playing the game. I feel like that's research, not videogaming.

Thank you for reading.