Checking your website speed and having knowledge about how your website operation is, you can refer these web sites:
Google service for speed and operation test :
This service provides you a report of your website performance on different devices such as mobile or PC.
Using this report you can optimize your web site .
ping.com: This website provides you different useful information about your website status.
You can find your total webpage sizes and discover the reasons of your website slowness and see the broken links.
The website “gtmetrix” can also help you optimizing your web site and increasing speed.
“Webpagetest” is also another helpful website which you can see your website loading process.