RPM Problem? 2002 Honda Civic
 

Recently my Honda civic has been having troubles with the rpms. Initially when I would first accelerate from a low speed to high, the rpm would instantly jump to about 3500 rpm then drop back down to about 2000 after a couple of seconds, however as of today instead of the rmps jumping up, even when accelerating and pressing on the gas peddle as firmly as possible my rmps would not surpass 2000 rpm even at 100 km/hr. Any ideas of what is the problem and how to fix it? Thanks!