Like the thread says: question your teacher. Always. Keep asking yourself why a teacher does as he does. Why he makes you do things. If you do not understand, think, think hard or finally ask with an open attitude. Do not assume anything.
Really, I can see why you feel the way you do. You (probably still) assume you can only learn from your teachers or high graders. So when this condition is not met, you get frustrated. In Aikido you train with many different people, preferably those that are worse or better than you (i.e. teach and be taught). To train with an equally experienced partner is a waste, I think.
Your teacher has given you a precious thing: trust. and then you question that? It is not all bad to make bad judgements; you can only grow.
The connection you have with your teacher is (much) stronger than you realize
You'd better excuse yourself to him/her for not understanding any sooner. This will show your respect and faith in the teacher.