Hi Charlotte,
Stop worrying!
There's a recent good view of the Yavor Palace:
http://www.holidaytruths.co.uk/reviews/bulgaria/sunny-beach/yavor-palace-hotel/
If you've seen some bad ones don't worry. Some people have funny ideas. If you go to Bulgaria with an open mind determined to enjoy yourselves and you will.
Weather, we have a thread
HERE, but don't bother looking. Bulgarian weather like ours can be unpredictable, but all things being equal you should find it stonking hot in July.
Don't worry about bars, clubs and restaurants, you'll find your own and the only valid recommendations are from those who have been this season. What were good last year might not be there this, and could have changed hands.
Ladies of the night, no worries. They don't bother men accompanied by their own ladies.
There should be young people there from all over Europe, and for more general chat on Bulgaria we have
THIS thread.
Peter