Can i sue my landlord i have an email say from him sayin that he knew about the bed bugs and had exterminators come but it did not work lost furniture

If you have evidence of bed bug infestation you are entitled to a rent abatement and damges for lost and damaged property, because a bedbug infestation by definition makes an apartment uninhabitable.  The fact that you have the email from the landlord definitely strengthens your case. You don't say whether you stayed or left as soon as you discovered the bedbugs but if you stayed you had an obligation to mitigate your damages, meaning continue to try to eliminate the bedbugs. You have a good case.