I have been harassed and discriminated against for 3 years

I have done the appropriate things that my handbook told me to do and nothing has been done. After taking a 6 month long disability for mental stress, clinical depression and panick attacks from the work enviriomment I returned and have been treated completely different and I believe they are trying to mess with me emotionally like they get a kick out of it. I started to record conversations of things that management was saying to me that is defintely illegal. The last straw was the director of operations used my name in a meeting for my team indicating they all spoke to me complaining about the recent changes in job tasks and then a temp was cursing and using racial words and i notified HR. The temp came to me on the break and walked me outside and aroung the back of a car to disrespect me and put me down about my disability and how angry she was that i told HR on her. I came back in only to find the email i sent to HR on my desk printed from my email and it was turned upside down. I notified the corp HR and told her i felt unsafe and if i could go home. She said yes and not to come back until she calls me. She did, offering me a severance.....3 months.....i have worked 3 years for company. Do you think she offered this because she knows i have a discrimination/hostile work enviroment case aganst the company? and should i ask for more?