What Causes Missed Periods, Pyrosis, Stomach Itching, Weight Gain, Tiredness, Rib Pain?

Hi, I'm louise, 21 years old, I have implant and was having regular periods until just over a month ago, I suffer heartburn everyday, itchy stomache, gaining weight, and tierd, I'm also booked for a scan tomorrow to check my gall bladder as I was suffering sever pain under my rib, and I'm also being tested for alpha1- antitrypsin, as u can see I have a lot goin on, so do you think the missed period will just be stress? Thank you in advance - Louise