Brief Answer:
Widrawal most likely cause

Detailed Answer:
I read your question carefully and I understand your concern.

Those symptoms are not indicative of a threatening brain condition, they do not suggest focal issues like stroke, tumor etc.
In my opinion the most likely cause looking at your past history is for the symptoms to be in the setting of Percocet withdrawal. If you have been using percocet for some time it is known for opiates to deplete serotonin and dopamine levels. For that reason it might take several weeks for those levels to return to normal and many manifestations might arise like dizziness, anxiety and depression, muscle and headache, abnormal sensations etc which would well explain your symptoms. It should subside slowly over the following weeks. If symptoms are very bothering a small dose of a benzodiazepine like alprazolam might help, but should be used with caution for only about a couple of weeks as it on its own can develop dependence.

Another possibility to explain your symptoms might also be the viral infection which you mention, although it is hard to judge as you do not give much detail. There are infections like mononucleosis which can leave long lasting symptoms for many months.

I remain at your disposal for other questions.

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