I need help losing weight, help?

I need help losing weight. I am 100 pounds overweight, a lot I know. I've been trying to get healthy this past year and even started taking exercise classes at school. I've been working out 5 times a week and eating a lot healthier. I'm still having trouble losing weight. I don't know what I'm doing wrong. My first goal I set for myself is to lose 2 sizes in 4 months which I have to do because my mom ordered my wedding dress in a 14 and I'm an 18. I'm 20 years old and 5'6. I have an hourglass figure so I have my fat spread all over my body not just in one spot. If anyone can help me I'd be very grateful. Also, I don't have a lot of money because I'm in college so cheap ideas would be best. Thank you.