Gym but weight gain on scale HOW?

Does this happen to anyone else? Ive started gym again after ages and I have been doing cardio...its been 2 weeks and the scale still says im the same weight and/or im gaining weight. I feel a lot slimmer though! My stomach is getting flat. Someone please tell me that this is normal and im gaining muscle when loosing fat and muscle weighs more lol! My diet is healthy too!

Ps when i get worked up i always forget that if this body change is normal for me. I think it is...I remember last year same thing happened and I eventually did loose weight but now i feel like giving up as i have an event to attend in 4 days and i feel like a whale looking at the scale.