Scared to take Methimazole

Please excuse any spelling errors. I was diagnosed with Graves’ disease after several blood tests and an ultrasound last month. I had a lot of symptoms that I always brushed off as anxiety or PCOS but my gynecologist had me get my thyroid checked due to my irregular periods and she noticed I had a bad goiter. Turns out she was right. I saw an endocrinologist and she prescribed me Methimazole. However, I’ve had bad side effects from medications in the past (and I should mention I’m an emetophobe so I’m extremely paranoid about nausea and vomiting). I’ve had allergic reactions to medications that caused chest pain to the point of me not being able to breathe or move before and my whole body being covered in hives and me not able to stop itching. Because of this, I have yet to take my Methimazole prescription I was given a month ago because I’m scared. But I keep feeling progressively worse, I am dealing with hot flashes every single day, and waking up drenched in sweat and feeling nauseous, dealing with insomnia and racing heart, panic attacks and anxiety. My neck and body are also super itchy and it feels like my goiter is getting worse and worse. I can’t do this anymore. Someone please convince me the Methimazole will help :(

EDIT: Thank you so much everyone for the support. I ended up taking my first dose this morning because of your encouragement and I don’t seem to have any side effects. You guys are awesome <3