No action on the airlock

So I am in the middle of my second batch ever, and am using a 6 gallon food-grade plastic container to ferment it in. It has been a week and i have seen no bubble action in the airlock, so I assumed it wasn't fermenting. So I opened the lid (you can't see through the sides since the plastic is very thick) and to my suprise it was fermenting well. Is this normal? It doesn't seem like it to me...I'm not really stressing since its fermenting, but I was hoping someone could explain this

CO2 is probably escaping from somewhere. Are you sure the lid shut all the way around, this can be a common problem. It might be the grommet, the little rubber piece that you put the airlock in, it could be torn or damaged, therefore you aren't getting an air tight seal.
Either way, RDWHAHB

Your lid does not seal very well or the gas is escaping round the stopper. I bet your lid does not have a gasket.

i beleive the problem lies in the grommet...it broke off when i was putting in the airlock, so i tried to create my own airtight-ness by using a ziplock bag and some priority shipping tape. It seems like it would be safe to say that this is the problem. I guess now I am just hoping too much bacteria doesn't come in, and it still turns out okay.

The only way to tell if your beer is fermenting is with the hydrometer. CO2 will find ways to escape around an airlock which makes them bad indicators of activity.

A good place to buy a grommet is a smoke shop.

Buy several grommets - you have yet to drop one into the barrel!

gas always takes the path of least resistence...so even the tiniest pin hole in the grommet hole will cause zero airlock activity.

but since its still fairly closed up, you shouldn't have a risk of infection.

I've had the same problem. I had my primary a little tooooo close to the Banjo burner one night and it warped the plastic a little. Didn't think much about it, but didn't get any airlock activity. Popped the lid and could tell that it was fermenting, so I just let it continue. Well, that was 4 worts later and I'm still using it. Beer comes out fine. I figure WTH? As long as it's fermenting, I don't really care if the bubbler is bubbling or not. I know that there is a good coating of CO2 on the brew, so let it continue.

Aright cool, i think that all the material i've read on brewing has scared me to leave even the slightest hole for air to peep in, or do anything w/o 100% sanitization. But from most of your guys stories/experience it seems like its okay to slip just a little bit

If the wort is fermenting it is producing gasses which pressurise the barrel and prevents anything entering due to the differences in pressure.
i.e. Dinnae worry aboot it.