You have a pretty positive relationship with work/life balance and only occasionally run into issues. Currently, you are not at risk of reaching burnout. Continue working on maintaining your healthy habits, and stay aware of how you perspective looks at the world when things get more stressful.
You are occasionally running into days throughout the week where you feel more tired or hopeless. Because of this, you may be in the beginning stages of burnout. Take some time each week to make sure you are resting and re centering yourself around God before filling up your schedule and mind with your to do list.
Most days, you feel like you are running on empty and can't seem to find much to look forward to (other than trying to get sleep, which isn't going great either). Girl, you are on the road to burnout, and moving fast. You need to make some changes to avoid major burnout - take a look at what you are committed to, and shorten the list down to things you are passionate about, are growing you, and are necessary. Make sure you are getting enough sleep (7-8 hours), and take comfort in the fact that there will always be a to do list - it's okay if things fall over to the next week.
Girl, you are in BURNOUT. You are probably feeling completely hopeless, exhausted, and want to bury your head in a pillow for the next year. Now, I'm going to recommend something DRASTIC - take time off. If you can't take time off, ASK FOR IT - and if it's still a no, maximize on the time you have free. Then do a re-evaluation of your life. First, re center yourself in God, and ask Him to lead you towards the purpose for your life in this season. Get rid of commitments that don't align with that. Spend a day coming up with a weekly schedule that will allow for a day (or evening) of complete rest, away from work and your to do lists, weekly/daily workouts (to improve your mood), and a healthy routine that includes activities to both grow you as well as incorporate things that you love. You may come out of this with a whole NEW direction of life - don't be afraid of it! And don't expect change to happen instantly - this is a long, grueling process, but it is absolutely worth it.