Stick with it my friend. Maybe try to have a little more continuity of lessons of you can. Try to have 2 lessons 1 day and 1 dual the next day followed by your solo.
You actually did the right thing if you felt how you say you did, recognising your own limits is a very valuable lesson in itself and to me shows that your thought processes are really sound.
Remember, your instructor won't send you unless you are ready so you are actually ready. Don't doubt yourself, think positive. Its a great experience going solo, I still remember mine in a Bell 47 31 years ago!
Good luck and please do let us all know how you get on.