Close. I think the expression you're looking for is "low on". You could also say "short on" in some cases. I don't think there's an actual rule, you just have to know which sounds better. What you wrote is understandable though. This is a finer point. Lately I'm low on energy because I am cramming for my upcoming exams. As a native speaker though "low on energy" doesn't sound quite right to me here. I might say: "Lately I've been tired because I've been cramming for my ( upcoming ) exams." Based on the context, I would know that your exams are in the future, so you don't need "upcoming". Sorry, I am afraid I won't go out tonight because I am low ( short ) on money ( cash ). I wanted to bake an apple pie but I couldn't because I was low ( short ) on eggs.

All good sentences Sara. I am a little short of words at the moment so I cannot give you an extended answer. I was short of breath yesterday, after doing some heavy lifting. I am a little short on compassion right now, because frankly my dear, I don't give a damn. I am a little short of enthusiasm because I just spent a day running all over town and have no interesting in going out for fun. I am a little short of insight on this subject because I have never read anything about it. I am a little short of interest in dating because I am focusing on my school work. I am short of cash because I have not been to the bank in a week.

There may be regional differences in English here. The last two certainly sound fine to me - they are pretty close to what I would say in the same circumstances. I would not use 'low on'. The first one is OK, but doesn't quite sound right. It would be more natural to say 'I have been'.