i'm sorry you're going through this, brain tumors are my biggest fear as well. but as for your twitching, it's a natural response to anxiety and a vast majority of the time is completely benign. muscle twitching can be caused by tension, and when we're anxious our bodies naturally become tense even if we don't notice it. the muscles of the face can stiffen up, causing the eye twitching that you described (which i get all the time as well!)
if you were having a seizure, it would be MUCH more noticeable than just some twitching. brain tumors aren't subtle, quiet things; they cause huge symptoms that can't be ignored, and the seizures that would come from a brain tumor would be unmistakable. also in the time that your twitches started, if you had a brain tumor it would have been giving you MANY more symptoms over the course of seven months, not just twitching here and there.
as for your ct scan, i highly doubt any tumor would grow in that amount of time since you got the scan. however i can relate to that sort of worry, and it's very typical of hypochondriacs to worry if a test was done "too early" to catch something like a tumor. it's a pattern of thinking that's extremely common with anxiety. but ct scan results are valid for a long time, and the probability of something growing in your brain later on that wasn't caught in a scan is very unlikely.
i hope that maybe i could be of some help to you!