<human>: Provide a brief overview of the text.

J (friend) and I have known each other for awhile now and we've always had each other's backs. He's helped me through some rough times and we each go to the other with our various worries about the future and what not. He's always been a grump with a heart of gold and despite what he claims he's a nice guy.

But for the past month or so he's been really off. I feel like it started after he went to this party and **something** happened that he wouldn't tell me about, ever since then he's been really distant. 

We went from talking at least 3 times a week to *maybe* once. I know he's been busy, and so have I so the drop in contact was expected. But recently he's done something completely out of character. He said he couldn't come to my birthday because of a big test and then proceeded to completely forget my birthday altogether. I later learned that he was actually running in the local electric run. I haven't talked to him since last week, a couple days before my birthday, as he was pulling an all nighter and was presumably busy studying and stopped responding after awhile.

I'm just really confused and wondering why he's seemingly changed into a whole other person in such a short span of time...
<bot>: Friend has started acting weird after attending a party where something he won't tell me about happened. Went so far as to lie to me for something kind of dumb.