Be careful about the gum. The artificial sweetener could be messing with your metabolism, especially if you are constantly chewing it.
Also, some people suddenly start eating foods they never really ate pre keto, you could be retaining water from ingesting something new or to which you may have an intolerance.
Next, sometimes people do gain weight at first because their body does some healing and the weight loss comes later.
Finally, I am a 5’3” 120 pound female. I think I eat about 1500 calories a day. You are eating not that much more than I do. You could be stressing your body with the increased cardio and not enough calories.
Until your body learns how to metabolize fat efficiently, the usual newbie suggestion is to eat more fat when you are hungry. Also, make sure you are getting enough sodium. Low sodium can also make you feel hungry. Some people find they need to supplement salt. About 2 teaspoons of salt, 5 grams of sodium, via food and supplementation.