I've been cycling on and off since 2019 and have seen some improvements, but my speed hasn't increased much. I used to ride 3 times a week, covering distances between 40 to 60 miles, with each ride taking about 3 to 5 hours depending on the terrain and distance. My average speed was 16mph, but it hasn’t gone up. I've tried various methods to increase it, such as changing routes, doing sprints, and gradually building up speed, but nothing has worked. The longest ride I’ve done was 80 miles, which took me 6 hours. I want to improve my speed and reduce my time, but I feel like I’ve been pushing myself too hard without seeing the results I want. These rides were two years ago when I wasn't working or going to school. Now that I'm in school, the stress and lack of sleep are setting me back to square one. I’m not sure what to do next. Any suggestions?