68' c4 problems, pls help with first pony

i've got a 68' 289 with c4 trans....here's my issue

if i put the car in drive or 2nd gear to start off and try to go, not gonna happen..at all, so for the past 2 weeks that i've had the car i've just been shifting through 1st, 2nd, and drive....now when i put it in first and start to give it gas, it shakes terribly bad and has an extreme loss of power....if i back off the gas a some (almost none, but still giving it some gas) it will work past the shake....to continue....when shifting into 2nd gear, it revs really high and hesitates for about 3-5 seconds before engaging into second gear, and the same happens on the freeway putting it into drive..no matter what gear im in it feels like a vehicle that is barely making it up a hill, even when driving on flat ground

any suggestions?
im not mechanically inclined at all so any help is much appreciated!
TIA

yea, my trans fluid leaks so i carry fluid with me...its not the fluid, that was the first thing i checked and it didnt do anything