Why am I unable to push the gas pedal of my Honda CivicEX 1998?

I was out for 5 months and my car was sitting idle. Later I came back and found that car's battery died. I replaced it. However, while replacing, one of the nuts from battery terminal wire fell down inside and I could not find it. So I thought it might not be a problem. Later on I used another nut and connected the battery. My car started fine and I just rolled it over in the parking lot and parked again so that I could use it next day. However, today I noticed that I am not at all able to press the gas pedal of my car and so it cannot move a whole lot other than just about 1-2mph that one usually gets when car is on D4.
Please help me and tell me what should I do? I will really appreciate