frustrated..

My name is Erika, I am 24. In the last year I gained 20-25 lbs. I started a routine of walking my dog on a brisk walk 1-2 miles per day. I hula hoop with a water weighted hula hoop for 30 minutes, I do 50 jumping jacks, 50+ crunches and I alternate what kind of crunches, I do 15 standard push ups, I do 20 squats, one minute wall sits, mountain climbers.. and more. I keep increasing with each thing as my endurance increases. I also am renovating a home, and doing lots of house work. I don't sit around much. I eat home made meals every day and I add lots of veggies and cut out bad things like butter and other fattening junk. I only drink water and the occasional juice. I have not lost a single pound or toned up. I have been at this for months. I have never had a weight issue.. and I suddenly put a bunch on at once. They ruled out health problems and I have ruled out my diet being the issue. My doctor even agreed that my eating habits are excellent. I can't seem to gain muscle or lose weight.. any thoughts? I will start running again when I can setup my treadmill but I replaced running with brisk walks due to my dislike for running on concrete.

I guess I am not sure what to do about the sudden weight gain. It is as though all muscle disappeared.. I gained fat.. and my breast size became smaller. I also started to break out like a 15 year old. I was told my hormones are fine, my thyroid is within normal range, no deficiencies, and no other known health problems. Suggestions for a safe guaranteed workout/weight loss regiment? My diet is as good as it will get without becoming vegetarian/vegan.