Killing WP or Being Killed ?

Hello (last WP zip)
I am having lot of trouble with WP (???)
Questions (for WP Specialist of course) : is the Loop going crazy ? Is the DB dying or ?
Using WP for years I decided to use it as a plateforme for an History Website.
Example : Working over 3 hours on a post, having about 60 to 70 tags and multiple categories, save and autosave ok then sudently : the published version has no more tags, or better, when I recall the post and only have a blanco page (empty) in the admin.

Is Word Press strong enough to eat all the datas or am I trying to auto-screw me ?

This is really a problem as I am building only the skeleton of the website and I have 3 months hard work in my back.

Please note that this is not a post to send people to my page. I have enough traffic. It’s a issue for WP specialists and coder as I need to know if I have to leave WP and take something else or if I am doing something not allowed with my Word Press.

Thanks for Help (if any)
Gunter