We are an ecommerce lingerie website and we developed on Magento 2 in August last year, and are coming across multiple problems. Site speed being one of them... I'd be interested to hear other people's experience of developing on Magento 2.
Are you still developing the store or is it live now?
Magento 2's developer mode is known to be very slow but switching to the production mode when you are ready to go live will help improve the loading speed.
Besides that, you may want to look into some sort of caching like Varnish or LiteMage Cache which will speed up the frontend for your website visitors.
Finally, make sure that your MySQL is optimized for Magento (one example being Query Cache if you have enough Memory in the server to spare).
Before enabling any kind of full page cache I'll recommend you to make performance review of code(<< Snipped >>). Once you will sure that code optimised you can think about full page cache. Because if you will use Varnish, FPC or something else page will be quick on the second load only. Such things as filters, sorting and even product view will be still slowly that will affect your conversion rate. Even if you will use cache warm it will take time until everything will be cached and once stock update, product bought and etc some pages will be slow again.
Check for below optimization on general magento,