And welcome to the club!
I think a lot of us would say that they had no particular symptoms when they were diagnosed with dyskariosis from a smear test. I certainly didnt have any, and I have had regular smears, bang on time from the age of 21 (I am 44). Always came back as clear until this most revent one.
You should get a colposcopy appointment soon, where they will have a better look - it sounds a bit intimidating but it's really not that different from a smear, just takes slightly longer. If your changes are confirmed as severe, they will either treat you on the day, or may offer you an appointment for treatment later. Some places treat on the day and some don't.
Anyway, you can get plenty of info from the lovely ladies on here. It's normal to feel scared btw. I was bricking it, as this is the first thing I have ever had wrong with me in my life, but the replies from other folks who had been there really helped a lot.