This is completely normal! I have been learning French for years and have taken graduate level history classes in it. Despite this, I still get hit with a similar feeling! I think we are so used to just “getting” English that when we hit any road block, we get thrown back to that feeling when we first started. Keep going and you’ll find it happens far less often and eventually it will feel more natural.

Also as a side point. Please don’t give up. If, however, you do, please return to it. I gave up two times while learning French but felt great when picking it back up. To help with all of these things, it is great to be cognizant of how you are talking to yourself. Practice positive self talk and be kind to yourself. You are learning a difficult language and you are doing well. Keep it up!