Don't know what happened

[BKs50trimGST]

Last thursday i was driving out to burnsville to look at some furniture with a couple buddies of mine. I was going up an on-ramp after driving about 1/2 an hour when my car wouildn't let me shift into any gear at all. I usually downshift and for some reason it wouldn't let me put it into 3rd. I sat at the light for about 10 seconds trying to get it into 1st gear. Finally i pressed the clutch in one more time and it let me put it into gear. Lately is has been hard for me to put it into 3rd especially when i'm accelerating fast. When i'm not accelerating fast the car seems to shift ok, but I just feel like something isn't right. Off my shifting problems, my cars idle whenever I start it the idle is about 2100rpms until it gets warmed up,then it goes back down to 700rpms. Is that normal for a 2g 6bolt swap?