But, the Website and Server are reacting very very slowly for me. Is is possible that you sometimes just get a timeout based on load? What does the Load on the Server say when its a Machine managed by you?
The MX record of _dc-mx.d59a58dee788.naijajapa.com. tells us that you have proxied your MX hostname. The Cloudflare proxy does not pass email traffic. The synthetic hostname you see is an attempt to work around that limitation. It is always better to not need the workaround.
If your MX hostname is mail.naijajapa.com, make sure that it is set to DNS Only. Please see this Community Tutorial for more information.
Cloudflare seems to be working correctly. Cloudflare will help speed up the Requests for Static Content which should be the Most Request on the Side. But stuff like Sending of the Contact Form will be always slow when the Server is slow because Cloudflare itself needs to wait for the Server Response. But it will help with Static Content