I'm currently Plat V and I feel like I'm going to get demoted back down to Gold 1, how would I know when I would be demoted because I have taken quite a number of losses at 0 lp, about 8 or so.
Also if I do get demoted and then get back to Plat V do I get another shield from going from one tier to another or is it just a one-time deal?
how would I know when I would be demoted
You wouldn't, until you will get "you have been demoted" message. I'd say 8 loses is not enough, but you never know with MMR. Also mind that winning one game and breaking lose streak does not help you if you start losing again immediately after.
Also if I do get demoted and then get back to Plat V do I get another shield from going from one tier to another
Yes.
as far as I know there's no "Shield" your only defense is your MMR, as soon as your MMR is lower than your division you'll drop like a leaf in autumn, it happened to me, I lost a LOT in gold 5 and started loosing consistently until I reached silver 4 :S, I'm slowly climbing back up though.
I got the demotion shield warning form Gold V to Silver 1 after one lose and 1 dodge and I have a Gold V MMR.. so wtf ?!
