One carrot, at the most 2 is sufficient to get over each fence. The really low fences also don't require the use of any carrots. If Epona won't jump over the fences, it could be due to two reasons: 1 - not enough speed, or 2 - approaching the fence at an angle. Using all six carrots at once makes them recharge slower, usually you can just use one and then wait for it to recharge or use another one if you need speed to get over the fences. This predicament you are in is likely an indication that you are using up all your carrots when you don't need to, use one or two at a time when you need the speed boost and you'll have more than enough time to complete two laps.
Also remember to give yourself some time to speed up when you use a carrot, if you're too close to the fence you won't get speed fast enough to jump it.
It's a very simple troubleshoot and an even simpler solution, so I hope you're able to escape this predicament you're in!
I look forward to your next childish rant about trivial matters in these easy games you think are impossible, they're quite entertaining and I genuinely enjoy diagnosing the issues with no/minimal effort!
