How to deal with academic writing phobia

Last year I took leave from my university because I could not complete written work. My academic performance was otherwise very good, so I was labelled a perfectionist. (This was before my ASD and ADHD diagnosis). Since then I have used brain apps and posted comments on Future Learn and other MOOC arts courses to improve my skills in reading comprehension and summarizing and structuring written material. There has been encouraging progress. However, when I began more demanding course-specific work e.g. literary commentary or essay I became very fearful and uncertain. (Yet I have the module-info. and am aware of the requirements) Has anyone had the same problems?Would extra tutoring in the subject help?  I might be able to afford a few lessons.