Hi
I answered in another post, but try this. Here is what is happening. You are most likely on shared hosting and your blog is using high CPU usage and slowly loading mysql. I assume you have multiple posts already.
Your problem, or better all problems are in “permalink structure”. When you set custom to let’s say /%postname%/ it is great for SEO, but what wordpress does it creates rewrite rules for each posts. So if you have 1000 posts, you have 1000 rewrite rules. In normal web development you would have one set of rewrite rules. In wordpress you have rewrite rules for each post!
How to fix it?
Change your permalinks to:
/%post_id%/%postname%/
OR
/%year%/%category%/%postname%/