strange new eating obsession?

im pretty sure obsession is spelled wrong...maybe not...it looks wrong though...hmmm
well on to my point of this post..i have this strange new tendency. strange for me at least...i already tend to not like things that are high calories for one serving. even if the only thing i eat that day. but i could handle eating a normal amout of lower cal things like vegies.  lately though i don't like things that more than 150 cal. at all. and even if it is less i tend to not take a ful serving. and then i can't stand that feeling of not being empty. even if its just water in me. it just makes me feels so ful...
is it "normal" for a persons "eating issues" as i like to say, evolve strangely like this?
p.s. im also like a vegan police for what goes in me. i can't handle real egg whites or butter etc. which i was semi ok with before. and its makeing me so grrr at people if they add non vegan things to the meals i cook that tend to be completely vegan
iny ideas or thoughts?