I think I have Dyslexia

Hi, I'm a seventeen year old girl and I think I may be dyslexic. I spell way worse than I should considering my age and intelligence. At first I thought I was just bad at spelling but reading up on dyslexia now I am unsure. Often when I spell something I might spell it completely differently in the same sentence. Although I learn of rules and things (like i before e except after c etc.) and if asked I will apply the rule but when writing I'll get it mixed up. I find it near impossible to sound words out too. When I'm writing I often mix up similar looking letters such as p,b and d.
I also mix up my words when speaking, I'll call someone by the wrong name even someone I know really well and not even notice it, or mean to say one thing and say another instead(ie the wall is blue when I mean red etc.). I can read perfectly fine to myself - I'm actually quite a quick reader - but when I read aloud I skip words or stammer over simple words. When I read or write a number I often mix the digits up and if it goes past a thousand and there is no comma I cannot say the number without really looking at it.
What I want to know really is if I'm dyslexic and where I can go to get information/help etc.