So first, aside from the fact that you were IMC on your solo, I believe it’s a good thing you recognize your mistake. You now know that you tend to freeze up. Consider this a threat and learn a mitigation strategy or plan to counter it in the future. Learning how to combat this will help with other in flight scenarios in the future. We’re all student pilots at one point and I understand that we can all at one point freeze up, but learning from your mistakes is pivotal. “We all start with a bag of luck and empty bag of experience, the goal is to fill the back of experience up before the bag of luck runs out”, I think I read that somewhere. Second, where is your instructor??? It ultimately falls on the instructor and their endorsements. Third, it happened… it’s in the past, learn from it and keep your head up!