Am I overweight? 5'10" and 143 pounds...? Major body image issues...?

I am 5'10" and 143 pounds and for the past few months I have been overly concerned with my appearance. I took a vacation and after seeing pictures of myself, I resolved to lose weight. It's hard for me to lose weight because I'm active and eat a healthy diet. Do I need to be concerned with my weight? How can I improve my plummeting body image?