Cloudflare makes website slower performance

Hi team,
My application is deployed in heroku(Rails app) and Domain from GoDaddy. For DNS I used CloudFlare.
When I open heroku URL of my application it opens much faster than domain name URL which is used from cloudflare. Please look into it.

Heroku URL: https://yug-print.herokuapp.com/
CloudFlare URL(with domain): https://yugprintopacks.in/

Done. That “Cloudflare URL” isn’t even using Cloudflare.

As It was not working. I have to switch DNS server.

Actually I had to execute some javascript code to close my loader it was working fine with my heroku URL(https://yug-print.herokuapp.com). But with Cloudflare I was not able to understand why it is not executing that code tried more than 20 times deployment even checked checked local with production mode each time. After Getting frustration, wasted 2 days I had to switch it to other domain name server. It was blocking users to see website.

and even website was loading too slow.

Let me know once @sdayman you are available for help. I will switch my dns Server to cloudflare.

@sdayman Please reply.