No Fermentation?

Greetings, Brewers!
I have 2 five gallon batches under my belt. Both wonderful. My 3rd batch was boiled and transferred to the fermenter Sun. the 18th. (3 days ago)
After I added the yeast, I noticed that the level wasn't quite 5 gallons. I had water handy, which was cold. I topped off the fermenter with this water- probably a half gallon. I have yet to see any bubbling from my airlock, and today the liquid level in the airlock actually leveled off. (s shaped airlock) So today I carried the fermenter upstairs, where the temperature can be better held around/just above 70f. (Basement more like 64f). Any advice or admonishments for me?
Should I fear that my beer is not fermenting? (I don't plan to move it around any more, btw)
Thanks!

a few questions
What was the beer style and OG?
What yeast did you use?
Did you make a starter?

Chill. It's just a slow start from the cooler temps. Moving it into the high 60's to low low 70's was probably a good move. I wouldn't panic unless you see no change in your OG for a week or so.

Northern Brewer Extra Pale Ale. Dry ale yeast that came with the kit.
I added an ounce of Crystal hop pellets to the recipe, which I added at 15 min. left in the boil. This was the first time I have measured the OG, and I don't know if the result was due to particulate matter in the sample, but I read 1.085. I allowed the sample to sit a few minutes, but the reading was the same. That seems high, right?

For an extra pale It does. What temp was the wort when you took your reading? Does water at 60F read as 1?
Either way aiptasia is probably right. Just give it time. RDOHAHB

Hydrometer reading from plain water just a minute ago was right around 1.000.
I wouldn't vouch for the temperature, though, it was cold tap water.
(It's my understanding that temperature variations on hydrometer readings are slight.)
When I grabbed my beer sample with the thief, I got a fair amount of "bottom crud", and hop floaties, as the recipe called for a hop addition with one minute left. Could this have skewed my gravity reading?

2 things that can throw off your readings by quite a lot.
1. top off water not mixed in well enough (ie... you grabbed a pocket of heavier wort when you sampled)
2. bubbles tend to form on the hydrometer causing it to float higher than it should. (give your hydrometer a good spin when you place it in the sample.)

Menerdari, you have shed some light on my gravity issue. As it turns out, I took the sample from the brew kettle after it had cooled-- not from the fermenter with the "top off" water added. DOH!
As for my -maybe- lack of fermentation, I will be patient.
Thanks, all, for the advice!