Never stuttered when alone, now I can't stop.

Never stuttered when alone, now I can't stop. I've been a lifelong stutterer, but one thing has always remained constant. When I read out loud, no matter what, pronouncing certain stutter inducing consonants has never been an issue, until about 2 weeks ago. I was practicing my speech because I speak quickly and it's a bit sluggish, when I noticed I stuttered sometimes when pronouncing "S" words. Fast forward to now; B words, G words, R words, D words have all joined the party. It seems like I traded my ability to not stutter when I'm alone for more coherent speech. I'd like to know why this is happening, though. Is it just a mental/social thing or am I fucked up? ​ Edit: Thank you to the people that responded. I'll agree that I paid way too much attention to pronunciation and giving certain sounds more attention, causing me to stutter. I never did realize this, because I thought my stuttering acted up in moments where I was nervous(I also have anxiety) or self conscious.