Am I doing the right exercises?

Alright so I've been trying to slim down because I noticed that I'm gaining a little weight even though I don't look fat for some reason especially in the morning. So I run/wallk (80/20) for 15 minutes lift light to medium weights for 15 minutes and then run/wallk (80/20) for 15 minutes again. I do this because I don't like running but I figured that I can light run for a longer duration to make up for the calories I would burn if I ran for 30 minutes straight (because sometimes I just do this whole routine in an hour instead of 45 minutes). Will this slim me down? And why don't I look fat, could it possibly be that I have a lot of muscle?