Hip Issue

Ok, I'm trying to figure out what I am doing wrong. I lost approximately 35-40 lbs last year and have been maintaining at 130-134 lbs since last fall. I have continued to exercise 5-6 days a week 35-60 minutes of cardio. I am currently walking 3.5-4 miles a day 4-5 days a week. I walked 63 miles last month, so I'm kind of wondering why my hips have expanded again. I just measured and have gained 2 more inches back in my hips. UGH!!!! I'm so frustrated that all the shorts and pants that I was wearing end of the summer and last fall won't pull up over my thighs this summer! If I'm working out consistently and still counting calories (eating 1500-1800) a day except on the weekends when I splurge a little...maybe that is the issue. :)

Anyways, I just thought I would get some input here. Anyone else have this issue? Thanks in advance!