Overtraining can be a problem and also if you do the same exercise or similar routines for a long period your
body will adapt to this and they wont be as effective. Try mixing your routines up with 2 times a week cycling and 2 times a week jogging or swimming! You could also look at interval training rather than a sustained pace for a long period.
Sometimes you can feel like you are putting on weight when in fact you not, I had the same problem with my program where I felt I was at a stall with
weight loss and I was putting weight on but nothing had changed with my exercise and
diet. The problem was doing the same
exercises week in week out for about 2-3 monthst and my
body had adapted to it! I now alternate my program every 2 weeks to keep my
body guessing and started interval training instead of sustained exercise. With these changes I have found the best results I have ever had!
Hope this helps!