I have had to extensively use N95 masks in student life. Infact the university even provided the better ones with valve, and while useable during normal activities I would rule them out completely for use under very strenuous activities.

Seeing how you can't be sure how much dust you have inhaled as this amounts to pretty much pure guesswork and how you also cannot change it now, my advice would be to clean, plaster, paint whatever the basement so that the air becomes dust free again and forget about what you might have inhaled as its of no direct consequence now (I mean its not like you could undergo some treatment to undo the damage now, thinking about the matter will just make you anxious.)