I see no one responded, so here goes...
I am a self-diagnosed hypochondriac too! I hear it called a polite name of "health anxiety." Ha!
I am mole-ey too and actually had my first "atypical nevus" removed last year by a dermatologist. He did say melanomas are usually greater than a pencil eraser in size; but that a very early, beginning one could be smaller.
As far as changes, I think they've added a few to to the old ABCD thing...I just looked it up and it says there's an E now, for "evolving." Also now they talk about the "ugly duckling" mole, which is useful for those of us with a lot of them. It says you should look for moles that appear different from the surrounding ones.
Just a note. The lesion I had excised had me completely FREAKED OUT, because it changed incredibly quickly. It started off as a mole I've had forever and very quickly (within a few weeks) grew about 3 times its size and then partially flaked off. I figured I was in BIG trouble. Doc said it was an actinic keratosis, not really scary at all. So just in case it does start to grow, don't panic.
Unless the lesion changes quickly (although I know that's confusing, based on the above), I think you're okay until October.
One last thing, my dermatologist did say he doesn't believe in sunscreen as first-line defense. He strongly recommended tightly woven, sun-protective clothing. I've since begun a wardrobe of sunsafe clothes, including the SPF50 ones, based on his advice.
Good luck, sweetie. I know this kind of worry sucks.