Vendor vs SS

I have a question that might just be a me problem. i take pretty high doses of SS brands as my every day for the price and convenience. Last month i had a little money and got some vendor tabs for the first time. I have taken too much a million times and i get nausea and the dizzies but i close my eyes for 15 minutes and im good. Trying the vendor tabs i took too much and felt like i was having a full on panic attack, sweating, shaking, and the worst nausea and wobbles. this happened again today with a different vendor tabs I got in the mail yesterday. is there something different between the tabs that can cause this or is this a me problem? i have never felt like that in my life and i know it wasn’t the specific tabs