unless you are a national level competitor, dont worry about it.
if you want to worry anyways, eat more fat and less carbs. give it about a month for your body to adjust and you will be fine.
to reassure you, i can go upwards of 18 hours without food and do a 3 hour strongman training session and be fine. even hit PRs. it sucked ass at first, but i got used to a high fat, low frequency diet and i feel way better overall and dont worry at all about pre or post workout nutrition.