Facebook PPC sudden drop in impressions

So i was testing with their PPC program lately and yesterday i ran a campaign which took off to some point. My ctr was 0.13% ~ and i was getting a good conversion rate but then suddenly it all stopped, i mean literally the impressions went down to being stagnant and after a few hrs it started on its own again (i didnt monitor it then) and behold this new wave of traffic is shit it literally brought my CR from 23% to 15%

the heck is going on? did fb got 'smart' and sent me lower grade traffic after they found out i am getting good clicks at low prices or is someone else bidding against me ? I doubt it is a competitor cos i am still getting clicks and my ctr on fb is maintained and went up abit but it's the conversion that is pulling me down. Anyone got experienced this before?

1. How many clicks did you get altogether? Your backend conversion could be calculated on too small traffic sample.

2. If you are right, then this usually happens when you have a good campaign going and you decide to increase your budget, say double it. I know many disagree, but in my experience, at that moment traffic quality always drops a little. Of course, it depends from targeting group size, targeting and other parameters... But even if the quality itself doesn't drops, the FB ctr will and you'll end up paying more. This is normal scaling-up problem and it's even more painful if you're targeting isn't 100% exact.

Try to target more specific, create more smaller campaigns with separated daily budgets.

It was close to 200 clicks when i paused it. Yeah i ran out of budget yesterday and increased it overnight but then the initial traffic 'right after' i increased budget was still fine. It was crap after some moments from increasing the budget then it all stopped and crap came in when i was asleep LOL. Everything else is the same i just don't get what it stopped all of a sudden.

Well gonna go test test test again today