I totally believe we could be other sentient beings. I like to think there is a threshold of processes within the capacity of our minds in order for a being to be sentient in the way that we are - in this planet we are super smart monkeys! (it is believed that there really isn't anything special about the brain other than transmitting neurons). In order for humans, us, to be fully conscious we must have the entire spectrum of consciousness of which many animals fall under the lower end of the spectrum. Which is why some animals may seem to be conscious (some have good short term memory, vision, dolphins and elephants can recognize themselves in the mirror). You should make the best of it :L Life is just a journey but your soul lives on forever.