Hello. Is there any way I can temporarily deactivate my entire Tumblr account (all blogs at the same time) to get it back a few weeks later without deleting it forever?.
No, unfortunately, you cannot temporarily disable or shut down your tumblr account. If you delete your tumblr account, that is forever and it gets shut down permanently, we can asure you that is almost impossible to get it back if you do that.
There is one method though, that would make your visitors believe you have indeed close your account, just completely delete your theme code, we mean all of it, and save. Also, you can try placing a redirect to any random page on the internet (more on tumblr redirects after the link). This way, your blog would appear just as a blank page, or get pointed to some other website.
Other options to disable your Tumblr Blogs “for a while” would be to password protect them, but that only applies to secondary blogs. You can also try by changing your Tumblr Blog url, but the people following you would find out since Tumblrs syncs the follower database with url changes.