What's you food habits??
Maybe you killin your workout progress eating wrong.
If you first started your journey into fitness you will have ups and downs in the beggining. As long as you track your food. Try and eat clean. Stay consistent. Push yourself while exercising. You'll be in good shape. Idk what your routine is or your diet. So I can not tell you where you are wrong or right. All I can say is do your research. Education is key for success.
You will gain weight when you gain muscle. Also, for some reason, the day after working out really hard, I gain weight but the next day or two it's off. Focus on your weekly/monthly weight chart in myfitnesspal. Healthy weightloss happens slowly. If you lose it too fast, it's more likely you will regain it.