Tips on focusing

Hi, I’m wondering if anyone has any tips on how to stay focused while studying. I am currently in the process of learning a new language. I don’t have a lot of time at home to study but luckily I have a job where I get a little bit of downtime between tasks so I try to learn there as much as possible. The first couple of months were fine but I’ve noticed since I’ve gone up a level in the language, I’ve been running on fumes. I’m starting to struggle on memorizing things and I can’t keep up my motivation. I know a big issue I have personally is just being tired, I’ve had insomnia my whole life and no matter what I do I’m lucky to get 5-6 hours of sleep a night. I’ve never had a real issue when it comes to studying before because when I was in school I just naturally retained everything and never had to study, my grades stayed pretty good. I’ve only ever had to study for one class and it was Spanish in high school. So all in all I’m just not used to having to study this hard for anything. If anyone has any tips on how to stay focused or motivated that would be greatly appreciated. Also if anyone has any suggestions on how to stay energized, I would welcome the advice.