Hello when i start my campaign i got 9/10 high quality score and everything was great and i got good amount of traffic then after 5 hours i got this (Rarely shown due to low quality score) and my ad never shown any more i got that for everyone of my keyword and i never changed anything so why my quality score go from 9/10 to nothing in less than 5 hours ?
Much smaller ad groups 1 - 20 keywords on phrase or exact match, very tightly matched to each other (very very very tight) and then specific ads written using those keywords in the ads. Also, don't use short tail keywords eg.) web sites Yes these have huge volumne, but you don't want that, you want quality. So in that example you would use words like: Cheap website design. In my accounts (lots of clients) I have 10/10 quality score for 65%-75% of all keywords and no lower that 7/10 for the rest, this means that the cost per click is usually under $1 and often under $0.50 even for very high competition keywords.
You need to sit down and learn how to get points added to your quality score. Build it back up. This is Googles game and you need to learn the rules.
try to be always mindful of the relevance of your keyword with regards to the page you are trying to bid. good luck!
Quality score depends on a lot of factors. The help bubble has a link explaining the factors that go in to quality score - give that a look and it should answer your questions.
Check keyword relevancy. You'll get poor QS if your keywords are not relevant. Check landing page quality. This gives you a QS=1. Most common reason for this is having a bridge page. Full Adwords policies and guidelines. If your keywords are relevant and a quality page, most of the QS is your CTR. Details about QS in the Adwords FAQ.