There is no connection between PTSD and epileptic seizures. Non-epileptic seizures (for which anti-seizure medications have no benefit and EEGs are usually normal) could be co-associated with PTSD. I am not sure what you mean by the EEG abnormality, if the abnormality was epileptic then you likely have a tendency to have epileptic seizures, but you do not state this. Anti-epileptic drugs are not reccomended after one seizure, unless there is an epileptic EEG or abnormal MRI. Klonopin is generally not a first choice anti-epileptic drug as it has problems with dependence and tolerance (decreased effetive ness over time). I sugest you see a neurologist to clarify whether you had an epileptic seizure or tendency to them or not. A normal EEG does not ruleout the diagnosis of epilepsy either.
Good luck