Yes. The mistake you make a is common one. Atheism and agnosticism do not lie on the same continuum, they are two entirely separate things. The atheism/theism/deism scale addresses what you actually believe, the gnosticism/agnosticism addresses what you think it is possible to know. Being agnostic in no way affects whether you are an atheist or not.
Looked at simplistically, there are 4 basic possibilities (ignoring the different possibilities of belief and just using "theist" to mean any religious belief):
Agnostic atheist | Agnostic theist
Gnostic atheist | Gnostic theist
The terms "weak atheist" and "strong atheist" are often used to refer agnostic and gnostic atheists respectively, although technically a strong atheist believes they
are certain as opposed to a gnostic who merely believes that it is
possible to be certain.
An agnostic atheist does not believe in god, but does not think it is ever possible to know for certain if that is correct. An agnostic atheist believes in god, but similarly believes that we can never know for sure if there really is one. A gnostic theist or atheist either believes in a god or not, and think that it
is possible to know for certain if that belief is correct. However, this does not necessarily mean that they think they do know for sure, just that it is possible to know in principle.
From what I've seen, it seems that the majority of people who describe themselves as agnostic are actually atheists. They don't really believe in any god, they just aren't so sure of themselves to declare that they know for certain, and realise that a truly omnipotent god could hide its presence and ensure that we could never know. This certainly seems to apply to you. You don't believe there is a god, you just realise that we can't prove the negative and therefore are open to changing your mind should evidence be presented.
As for your statement that atheism is a religion, as the saying goes - atheism is no more a religion than not collecting stamps is a hobby.