Am I "fooling" myself? As I practice more and more on seeing life as Dukkha, something interesting happens. I feel a greater sense of gratitude and contentment. 

I am not talking about seeing things as they are directly and non-conceptually, piercing through and seeing emptiness. I am a beginner, stuck in concepts. But the more I interpret my existence in view of impermanence/anicca, suffering/dukkha, and non-self/anattā, the more grateful and content I become. 

Am I "fooling" myself? Is it just another aspect of Dukkha, like when you are in love and don't see that it's going to end/change?
Here is the simple answer to what you feel...

We are in constant pain and suffering. 

As to lord Buddha 

Eyes,Ears,Tongue,Nose,Body &amp; Mind are Burning from three things (Lust,Anger,Confusion -[Raga,Dwesha,Moha]). But the one who practice and realize escape the burning forever,he is free.



So here's what is happening to you...

Now that you have started to see the world in the correct way you might feel these things like anyone who traveled the path before you,


Happiness or joy without a reason
Feeling happy even from the little things
Not feeling like you used to,as if you are someone else
Appreciating little things in life
Feeling more love or kindness towards ones who are close to you &amp; for almost anyone
More willing to forgive &amp; forget
Looking back at past and making plans to correct the wrongs and to
apologize


These are really few among the usual characteristics of an individual who is practicing the path. Feeling happy and relaxed, starting to enjoy the life without hassle is really normal and there is nothing to be afraid. What you feel is the slow process of realization, The realization of what truly things are.