[duo797]

If I may add to the conversation, I have a few things to say. First, it's best if you don't get so worked up about being called a liar over the internet. For one, you have only 23 posts, so you're an unknown quantity. Also, taking an aggressive tone is not going to make you any friends here.

Sashimister is just suspicious because we get a bunch of people who talk a big game about their japanese skills. Perhaps you can understand how frustrating it would be to have people who claim to be fluent giving bad advice to forum members with honest questions. Come across enough people who lie about their abilities and anyone would have a bit of a short fuse with people who appear to be misrepresenting their abilities. If you want help, my best suggestion is to just forget about it and show some humility when asking for help (I don't mean to sound aggressive when I say that, by the way).

As to your japanese question, ほど does mean extent or degree, like Jesselt said, but I doubt you'll ever find a translation that literal.

If I was to make part of the phrase just '切ないほど懐かしい' then I'm fairly sure it would mean something along the lines of 'So reminiscent it's heartrending'. 切ないほど is 'To the extent that something is heartrending/painful'. To put this into perspective (and intentionally ignoring なぜか because... well... I'd feel more comfortable trying to understand it if I had more context, but not with just this at my level), I would say the phrase is something like 'So reminiscent that it should hurt'. As always, if a more fluent speaker corrects me, go with their corrections.