Switch from Tecfidera to generic

Hi all,
I started the new generic dimethyl fumerate in December after 13 year’s on Tecfidera. I really have struggled with side affects i had when i first started on Tecfidera. Increased acid reflux, heartburn and flushing several times a day.
My nurse has advised to keep persevering but the last few fays have been awful.
Has anyone had a similar experience switching?
I understand there should not be major differences but something in it is not agreeing with me.
I am taking presciption meds to help but night time is the worst.
Thank you