I think is means: "It's only been 2 days (only two days have passed) since I've eaten eggs and steak, but I want to eat it again!"
If I'm right, then it's talking about time that has passed, but doesn't use the any sort of past tense, so I'm confused as to why that is. I know しか is used with a negative, but why does it use 経っていません instead of 経ちませんでした (past negative). If it's not something that's easily explainable, do you know of any sources that may clarify this for me?
Also, looking at example sentences that use 経つ, I see different conjugations that use both past and present, but the English translation makes them seem to mean the same thing. I've been told that they mean the same thing, and that some are natural, while others are not, but I can't seem to figure out why different conjugations are used to mean the same thing.