2000 Dodge Caravan Not sure what the problem is

I think my tranny is going out. When I hit the gas, esp when going up a hill or getting on the freeway it acts like it doesnt want to go like it almost stalls and shakes when I hit the gas. Im not sure what is causing this. I had some kid change my spark plugs a while ago and thats kind of when I noticed it all happening. I cant really afford to get it fixed so im hoping its something easy. It is just really weird iv never felt that when hitting the gas before its like I floor it and it shakes and doesnt really seem to go anywhere then finally catches on and goes. Any Advice please =)