Are my symptoms that of leukemia?

Hello I am a 17 year old girl and recently I've been going through some strange things with my body I have only recently pieced together, albeit skeptically, as leukemia. my body has been weak since a spectacular medical issue two years ago and I have been writing most symptoms off as an aftermath of that. However I recently formed a large bruise the likes of which I've never had before with no memory of how. I'm constantly tired yet have written that off as the anemia I was diagnosed with a few months ago. I lose and gain weight strangely and sometimes get pains in the joints. I'm getting a blood test soon but it would be wonderful if someone could calm my paranoia and tell me what's happening to me.
sincerely
a concerned teenager