there aint no way to know for sure, and thats one of the main reasons why people consider life is as nothing but a stupid unfunny joke

love just because of simply the act of loving or expecting something in return?

well philosophically speaking, you shouldn't feel bad about the past

well what do u do when a mosquito keeps bothering u or a spider scares the crap outta u, you kill it without a second thought
hows that different from killing for food
we are the most powerful species on the planet and in order to survive we need to eat or kill other creatures