Hi, shy bobcat!
How are you connecting to the internet? Do you always connect the same way, and in the same location?
When you sometimes do get a connection but not always, and when the response is slow, it's likely you have a problem with connection speed or quality.
It's always good to have a mobile app such as Speedtest (available at no charge from Ookla at link: http://www.speedtest.net/mobile/) to be sure you're getting the speed you expect.
I don't use a Kindle Fire but this will keep the conversation going, so others who do can probably add helpful info.
hth
Few things reveal your intellect and your generosity of spirit—the parallel powers of your heart and mind—better than how you give feedback.~Maria Popova