Thyroid problems or low iron?

Lately I’ve been having these little itchy brown spots show up on my neck and chest, I’ve also been experiencing vertigo, trouble swallowing, increased anxiety, mood swings, fatigue with insomnia, my hair is falling out and i feel like I’m not getting enough oxygen sometimes and pressure in my head. I know more than likely none of y’all are doctors (i have an appointment Monday) but I’m scared and Monday seems so far away. I went online which i know i shouldn’t of done but some ladies said they experienced these symptoms and it ended up being anemia or hyperthyroidism. I’m afraid that something is seriously wrong with me and i just want to put my mind at ease. Have any of you ladies experienced this before? Again i know none of y’all are doctors and probably don’t have answers I’m just really scared, I’m 19 and haven’t been so lucky when it comes to health.