This is link of my website sitemap http://downloadfreemovies.org/sitemap.xml . I was doing fine 2 days back had good amount of traffic on keyword download free movies, then it suddenly gone down. my site map is 14.25 MB, i have included 100 newer posts to include on sitemap. so around 128 pages for indexing. This is setting for sitemap i am using. Homepage Daily 1.0 Posts Weekly .3 Static pages Weekly .2 Categories Weekly .5 The current archive of this month (Should be the same like your homepage) Monthly .6 Older archives (Changes only if you edit an old post) Monthly .0 Tag pages Weekly .6 Author pages Monthly .3 Pls. advise me
I don't think sitemap cause issue in ranking; recently google has announce Site Speed as a Ranking Factor that might be problem better to check site performance in google webmaster tools.
As per google rules, XML files can contain 50,000 URLs per sitemap file and up to 10 MB. Try to reduce your file size. if needed you can create the multiple file size.