In need of motivation

Taylor
I'm currently 22 and a half years old, 5'5", and 143 lbs.  I've always struggled with my weight and appearance. When I was 16 I weighed 130 and I thought I was fat becausei looked towards my sister for sizing and she  was always smaller than me. I used to wear a size 4 and now I'm an 8 in some clothes and a 9/10 in others. I really wanna get back to that confident state 
I have a boyfriend who loves me for the way I am and I love that, but I wish more than anything that could shape up and drop a few pounds. We have been talking about getting engaged soon and getting married by next October. If I have to try on a wedding dress in my current state, I'm pretty sure I would cry. And not a happy cry, an ugly, ugly cry. 
So I need some help and motivation from you wonderful ladies on this app. Have you ever been in a situation like this? Have you ever lost a good amount of weight? If so, how did you do it? Tips, tricks, words of encouragement, anything will help. 
I'm going back to college soon and my apartment complex has a full gym and I'm playing on walking/running daily, any other recommendations?