You hit a brick wall because your brain has partially forgotten the material due to the break, and trying to force recall through repetition is causing frustration. The solution is to reset your approach: treat the review as fresh learning with a new strategy, not as a test of memory. Start by skimming the course materials to rebuild a broad overview, then focus on active recall with spaced repetition rather than passive re-reading.
First, accept that forgetting is normal and not a sign of failure. Your brain pruned those neural connections during the break. To rebuild them efficiently, stop going over the same few things repeatedly. Instead, create a list of all the grammar rules and vocabulary you learned before, then test yourself on each item once, marking what you remember versus what you don't. This gives you a clear map of what needs work.
Next, use active recall techniques: cover the English side of your notes and try to produce the Gaelic version, then check. For grammar, write out the rule from memory and then compare to your original explanation. If you can't, look it up, but immediately try to explain it in your own words again. Pair this with spaced repetition: review items you forgot after 1 hour, then 1 day, then 3 days, then 1 week. Apps like Anki (free, open-source) or Quizlet can automate this, but a simple notebook with dates works too.
A major tradeoff: you may need to re-learn some concepts from scratch, which feels like going backward. But this is actually faster than spinning your wheels on the same material. If you find a specific grammar rule impossible to grasp again, search for alternative explanations online (e.g., YouTube videos from different teachers) or write a simple example sentence and use it in a mini-conversation with yourself. The key is to engage with the language actively, not just read or listen.
Finally, set a small, achievable goal for the next week: for example, master just 5 grammar points and 20 vocabulary words. Celebrate each small win. If you still feel stuck after two weeks of this new approach, consider finding a language partner or tutor for 1-2 sessions to get personalized guidance. The dream job is still possible; this wall is temporary.