can i be fired for posting factual truths about my job on glassdoor even if it is mostly negative

Hi and thank you for your question. It unlikely that your employer would be able to dismiss you for just cause for posting on glassdoor. If you are dismissed, then you would be owed severance. I would strongly encourage you to visit the severance pay calculator our firm has developed to see what you would be owed if terminated (www.SeverancePayCalculator.com). I would also encourage you to call us right away if you have been dismissed.