I am feeling insecure about my singing in my music cl. Any advice?

I am 10 and doing a degree in education but taking music as my major. I am absolutely besotted with music, I am pionate in all area's from theory to instrumentation, but I struggle with the singing so much. My music lecturer is amazing and has spent countless hours with me. I am told that my voice is good and I can hear I am on key, the pitch is good all that jazz. I am happy to do my part in the choir but the moment I am asked to sing alone, my stomach drops and I feel like crawling under a rock and dying. My lecturer has told me this has to stop or I will be kicked out the program. Any advice?