I think you should get some friends who speak the language that you are learning. You have to learn the language in order to communicate with them and so you will become motivated again.

If you have the money, going to the country where the language is spoken will motivate you even more because you will become frustated when you cannot understand and happy when you can.

find something that makes you need to speak the language, i had never wanted to learn german until my brother learned, and wanting to know what he said made me want to learn it

watch movies or TV series,you'll find your interest come back
its really work
i try on myself , and the result is good