possible learning disability in addition to ADHD

okay, so this may be kinda long but i really need advice. I have always struggled academically. I started reading late and was never reading at grade level. I also have terrible spelling. When I was 11(I'm 19 now) I was diagnosed with ADHD innatentive type and started doing better. I also get really into the Harry Potter books and this helped my reading because I finally found something I enjoyed reading. I don't doubt or think I was misdiagnosed but I am still having a lot of academic problems and when I told my mom she said it didn't sound like ADHD(these are in addition to ADHD problems). I continue to spend about 40-50 hours a week at the library studying and it takes me twice as long as everyone else to take tests(I recently spent 4 hours on an exam). Here are some of my problems:

~I have terrible reading comprehension
~I could read you a passage and you would probably think I was a normal or good reader and it would be fluent but I would have no idea what I read
~I need to read things multiple times, stop to think about it and read slow to understand it but some harder level reading I just give up on like my psychology text book
~I often lose my place or skip to the wrong line while reading
~I often read words wrong the first time(a funny example would be that once I saw a sign and thought it said disco pants until my friend pointed out it said discount paints, though I usually wouldn't say that out loud but would just take another look)
~The words I read wrong usually begin with the same letter and have some of the same letters in it as the word I confuse it with. This usually happens when I am rushing or don't look at a word as long as I should.
~I can finish tests like vocab and multiple choice much earlier(I get extra time as an accomadation for ADHD) than say a math test but still I am always the last one done. However, it takes me almost always twice as long as the given time to take a math test because it is something that you have to comprehend as opposed to a vocab test where I can recognize certain words and terms because I have a good memory. Despite the long time it takes for me to take math tests I almost always get A's I just need the extra time otherwise I would only have half done
~many people call my spelling "inventive or creative", I can't really explain how I spell because it is like I said kind of inventive but sometimes I spell how it sounds and sometimes it is just completely off and with long words I have a lot of trouble sounding and spelling them out. I usually start out okay but then half way through it doesn't even make sense. I also get the different rules mixed up like I just spelled despite, dispight until spell ckeck caught it.
~I tend to gets words like where, were and wear mixed up or now, know and no.
~I do like to read but the books I choose are not hard for instance the percy jackson books or harry potter books are not particularly hard to read but when I tried to read "The God delusion" it was too hard and I didn't understand it even though I have a lot of interest in the subject.
~When I am reading I never read a chapter at a constant speed without stopping but instead always re-read, stop, go back and lose my place.
~Despite being a perfectionist when it comes to school I never read my texts because it just takes to long and I never understand them which just causes frusteration. It is uncharacteristic of me to slack on something like that. I am worried that this will hurt my grades the further I get into college.
~I honestly didn't know right from left until way older than I'd like to say and then used the make an "L" with your hands trick and even now I sometimes get them mixed up like if I am driving and someone tells me to turn right I might accidently go the wrong way.
~and don't get me started on standardized tests. I always do bad because I don't have enough time and the time limit makes me really nervous and makes it harder. I know I could score well if I just had the time I needed.
~I honestly know nothing about grammar, even the basic elementary stuff I am bad at, especially punctuation.
~I also tend to avoid reading at all costs, like I never read long posts or news stories that people send me with a few exceptions like if I am incredibally interested in it to begin with.

I know this is a lot, sorry it's so long. These are the academic problems I have that I don't think are ADHD related. I am just not sure what these are whether they are ADHD or are nothing or possibly a learning disability. So to sum it up my main problems are poor reading comprehension despite being able to read aloud fluently, terrible spelling, sometimes reading words wrong at first or confusing it with a similar word, slow reader and often skip to the wrong line or lose my place. Thanks in advance.