I'm So Confused

My last minute preparations for the GRE (tomorrow, 8/14) are coming to a close. The hardest part for me is going to be the antonyms. I took an online practice test yesterday and a paper one today. Yesterday, I got the question:

DISSIPATE:

Answer choices: wander, coalesce, oscillate, exhume and restrain.

My brain went to the mention of dissipation in the Bible. I recalled it being a sin, so I chose "E" (restrain). Wrong-o. It is coalesce, as to dissipate means to disperse. Then I recalled the weatherdude on TV saying that the rain shower would "dissipate," or go away.

Today, on my paper test, I run across the word:

DISSIPATED

Answer choices: temperate, pleased, inundated, encouraged, and planned.

Remembering what had happened on the previous attempt, I chose inundated. The reason being that if rain showers dispersing or leaving or dissipating, the opposite would be that we would be inundated. Wrong-o! The answer is temperate, because as the book says, "The word dissipated can be a pejorative reference to someone devoted to the pursuit of pleasure--the opposite of dissipation is restraint or moderation." So the answer was temperate.

The online test and the book are from the same company. In one place they say outright that dissipate and restrain are the opposite.

Ugh! My brain is beginning to ache.

I think that I am pretty much done studying. I cannot wait until tomorrow afternoon when this test is behind me. I know I will do well (I'm using positive self-reinforcement here).