Question about my funky tranny...

Was just out driving, and during the beginning of the duration every time I would shift into second, the stick wouldn't go in, and it would make a rubbing noise. After a while it stopped and went into second smoothly. It wouldn't do it when I was downshifting, only upshifting. It's not the synchros, is it? The clutch was all the way down when I was shifting, and it wasn't like I was powershifting or anything, just normal, everyday driving. Thanks.