Do I have a valid case for constructive discharge?

I was placed on 90 days performance probation or be subject to termination during which time the work environment became hostile and it became clear that my employer was not acting in good faith. As a result, I gave 2 weeks notice. The day before I gave notice I informed my boss of my possible intent and the reasons why, whereas his response was the he was not going to change. I would like to note that I gave notice to my immediate boss, HR Manager and the Senior VP of Operations which included references to the 90 day ultimatum and a lack of improvement in conditions. In the last act of bad faith, on my last day of employment my employer informed me that I would be obligated to repay relocation expenses since I had only worked 1 year of a 2 year agreement. Here are some examples of the unreasonable conditions and hostilities leading up to my notice: 1.)Personnel changes with my direct reports occurring without my notice, (2) Weekly meetings that I scheduled for performance follow up did not materialize, (3) Basic approvals once handled independently had to now be approved by my boss (4) My boss had several emotional outburst in front of myself and other employees in which he threw and kicked objects about the area. Again, I found these issues to create an unreasonably hostile work place and feared for my job given the 90 day ultimatum. These events made it clear to me that I would not be retained so I therefore put in my notice. I shared all this information with the HR Manager during my exit interview of which she recorded very little. My ex-employer is continuing to pursue the relocation reimbursement which I will continue to fight given these circumstances; however, I am considering a counter suit for constructive discharge.