Maybe stress from leaving a position you were familiar with to go to the unknown
Hello and welcome!
If you are working out right and eating right then conditions like hypothyroidism can lead to weight gain. Edema due to kidney disease, liver disease or heart disease can lead to weight gain. Medications like OCpills, antidepressants, pain killers, steroids all can lead to weight gain. Lack of sleep will make you gain weight. Lack of sleep makes you physiologically stressed resulting in fat storage. Stress makes a person eat more to compensate and leads to production of hormone cortisol that stores fat. If you follow these measures it will definitely help. If the problem persists seek professional help and get thyroid tersts, kidney tests done. I sincerely hope it helps. Best wishes!