Am I worrying too much, or could it be dyslexia?

My son recently completed his first year of school, and appears to be having great difficulty reading...he barely ped the "PALS" test but I notice he reverses his b's and d's often...his teacher said that was common at his age...but he also confuses 3's and E's sometimes, and reverses numbers every so often...like he'll tell me the speed limit is 5 3 instead of 3 5. He will often look at a word and "guess"...if it's the word "like" he may blurt out "look"...at the end of this school year his teacher stated that he was having difficulty with "sight words"--the, little, on, come....and rhyming. I think I may be seeing a problem that is not really there...I just see him struggle so much with his reading. My daughter, she is 8, has not struggled with reading and has been above her grade level since she began school. Did I fail him?...Did I not work with him as much?...Did I unfairly think that he would pick up reading as easily as his sister?