Acceleration problem. 2000 Camry

As I was going to the store today I was
going about 45mph and my car just
stopped accelerating, rpms shot up. It
would then put along at about 30mph but
no higher. I pulled into a parking lot. Went
to the store and came back out, started
fine, drive halfway through the parking lot
fine, I stop at a stop sign and again, no
acceleration but rpms jumped. I managed
to turn it on and off and putt it along to a
parking space. Checked my atf, was a little
low so I fixed that. After doing so though I
tried it again. Put it in drive, it engaged the
gear but when I let off the break it slowly
rolled backwards. I put it in reverse,
nothing. I have a cel on but can't
remember the codes, just remember one
was concerning the evap system. Any
ideas helpful as my dad (my usual
mechanic) won't be available to go out and
take a look until tomorrow night.