Such fluctuations can indeed be frustrating. There could be several reasons behind this. Firstly, it's important to analyze if there were any significant algorithm updates around the time you experienced the drop. Secondly, check if there have been any technical issues on your website that might have affected crawling and indexing, such as broken links, slow page speed, or mobile responsiveness. Moreover, since your casino website involves sensitive content, Google's algorithms might be scrutinizing it more closely, especially if there have been changes in their guidelines or policies. Also, evaluate your backlink profile to ensure there hasn't been any spammy or low-quality linking that could have triggered a penalty. Considering the complexity of the situation, I recommend seeking professional help from an experienced SEO agency like
https://en.site-ok.com/. They can conduct a comprehensive audit of your website, identify issues, provide strategic recommendations, and guide you in recovering your rankings. Remember that recovery might take time, but with the right approach, you can bounce back stronger.