Hey Tokey... This looks most definitely like a nitrogen deficiency - but since you don't have a diary, all you're going to get here are guesses because it could be something else, too! Is your PH in a good range? This could be a lockout issue where you're giving enough nitrogen but the plant just isn't able to absorb it... in that case, you'd need to do a flush and start your feeding over again...
Do yourself a favor and start a diary so that when you have questions or run into a problem you need help with, the community will have as much information as possible to help you out!
Good luck!