Suggest Treatment For Pimples

I'm a 37 year old female. 4 months ago I weighed 62kg, now I weigh 69kg. I am always tired and feel overwhelmed and somedays even depressed. I also breakout in pimples on my face which has never happened to me before ever. I went for a thyroid test 2 months ago and it came back normal, but with slightly elevated cholesterol. But over the past 2 months, despite going to the gym 4 times a week with a trainer and being on fairly strict diet, I have not lost a single kg.
If it is not my thyroid, what can it be?