I think my synchros suck

[Gismo R]

A lot of time when I shift into third it grinds like you wouldn't believe. It's mostly when I shift from 5th down to 3rd, but also happens a lot when i'm trying to shift quickly from 2nd to 3rd. It didn't use to be this bad, it would only happen every now and then; I thought it was just me not putting the clutch down fast enough. But now, when I shift from 5th to 3rd, and trust me the clutch pedel is completely depressed, It grinds every time. And it doesn't matter how slowly I try to shift, it grinds a bit then goes into gear. It also does it sometimes going into 5th, but not as bad. I have no problem at all with grinding if I put it in 4th then straight into 3rd or 5th without releasing the clutch. So, what's up with my transmission? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'> I think it could be my synchros but I'm not sure. Please help!
Thanks.