My toilet cant flush what should I do

Septic System?? If so, the system is FULL of water already and needs to drain out from your drain field. If it is a municipal system, tree roots CAN SWELL TO 40 % or more of their normal size in wet weather, creating a blockage- hence a slower drainage- I'd look into a rooter service if this is the case and if on a Septic System- even pumping the tank will not help as the ground water is the culprit-preventing more water to disperse. Pumping the tank will only remove liquid & solids in the inlet side- not removing water from the leach/drain field.

Sounds like the flapper is leaking and/or broken altogether. See instructions on replacing a flapper here: http://www.wikihow.com/Fix-a-Flapper-on-a-Toilet

See other possibly useful answers here: How can I fix a toilet that flushes incompletely? and here: Why do my toilets flush slowly and often incompletely?

EDIT: Um, after re-reading the question, I wonder if the toilet isn't simply clogged. Does the tank re-fill and water stop flowing into the tank after flushing (you can hear when water is flowing)? If the tank re-fills and water shuts off, it isn't the flapper. If the tank re-fills and water stops, then it sounds more like the toilet is simply clogged. Did you try a plunger? If that does work and the tank does refill properly, then you'll need the drain snaked I think.