My Dog Has Been Having The Following Symptoms, Lethargy, Disoriented,

My dog has been having the following symptoms, lethargy, disoriented, siezure like episodes - padding legs, stiff right front leg, tilted head, rolling eyes, she's not drinking water the whole day and having a hard time sleeping. What do you think is wrong with her?. The seizure like episodes has been going on for a while but is getting to be frequent the last couple of days.