What should be done?

I have tried to explain things about my car and I've
yet to receive good detail about what it could be.
This started at the beginning of January.  Now if
I'm just sitting, or maybe stopped at a light or stop
sign, my car starts shaking aggressively.  But it's
not just one motion, it'll shake and stop. Shake and
stop. It's a retested process unless I'm driving.
While it shakes, the RPM mimics that motion.
When I go to drive from wherever my car was
stopped at, It'll act as if the car is hesitating to
move and randomly accelerate at random times.
I've also noticed today that while I'm driving, it's as
if I'm trying to break while gaining speed.
Something is trying to slow my car down when I
should be going 50 MPH. I can have my gas pedal
to the floor and my car won't reach the speed it's
supposed to be at. It's as if my car is dragging a
semi behind it.