Switching Up My Cardio

So today for the first time I fully committed to jogging in intervals. I do 1 minutes jog and one minute walk then after 3 cycles I go to jog 1 minute and walk 2. I am excited because I was never able to jog on a treadmill before for more than 30 seconds. I hope this will help me because I have been eating healthy and working out 4-5 days a week but the last 3 weeks I have been gaining weight instead of losing I am still motivated in spite of this but it is very frustrating.