How much compensation do i deserve?

I suffer with mental health and get my medication from a pharmacy as usual. I was given the correct box with correct label and wrong tablets in box. I was unaware and took the wrong tablets for six days. Not only did my mental health go down hill and i felt the affects off coming off my usual pills. But also the stupid pills i was given gave me a water infection. The company are trying to brush it under the carpet and trying to offer me early settlement. I don't know what i deserve and plus i feel bad taking money from them. What should i do and if they do offer a sum how much should i be?