Wordpress website with cloudflare down 98%


I have a wordpress site, I added it to cloudflare. Issue started where, my wordpress page used to load very slowly and when i update/create new posts, Error 502 Ray ID: • 2018-08-06 02:25:39 UTC
Bad gateway

I have researched on internet and created two page rules on my website link/wp-admin and wp-login pages and disabled performance and apps. it worked for 1 or 2 days, and same issue again. now, everytime I post a new post, it gives same error, today it was so pathetic. I cant even login to my admin account. Is it something that issue is common with free account ? Even now, it says this: This page is currently offline. However, because the site uses Cloudflare’s Always Online™ technology you can continue to surf a snapshot of the site. We will keep checking in the background and, as soon as the site comes back, you will automatically be served the live version. Always Online™ is powered by Cloudflare.

When I pause this website in cloudflare, it works fine, which is directly connecting to my site without cloudflare. Any suggestions?