It’s going to sound like an obvious cliché answer, but just try and keep yourself busy. Fasting forced me to take up a myriad of new hobbies. Alternatively, I scroll through weight loss and progress picture subreddits to stay motivated (as I’m doing it for weight loss). Boredom is unfortunately the hardest part of fasting (for me at least). Goodluck!
If not water fasting a cup of tea usually helps me, occupies me with the taste! Try to do something productive like taking a walk, writing, reading. You’re at 43 hours, your brain is doing everything in it’s power to get you to eat. Once you get past this your fast will be a breeze.