Definitely call your local poison control center.
That said, I doubt you got a lethal dose. 25% of a few drops of a anti-freeze/water solution works out to be a truely miniscule amount. Have you eaten anything un- or under-cooked recently?
Ethylene glycol poisoning in small animals typically leads to kidney/renal failure. Poisoning is detectable by crystals in the kidneys and consquently the urine. Symptoms in cats are similar to alcohol intoxication. There is no antidote for feline ethylene glycol poisoning. Dogs are more lucky as there is an antidote that is fairly effective if administered soon enough.
Humans have a huge advantage over most small animals: mass. The amount of poison required to adversely a human is generally significantly greater than that of small animal.
The real danger of ethylene glycol is not that it's just poisonous, but the fact that it is also known to taste pleasantly sweet. If it tastes good, it can't be poisonous, right?