I've been trying to work on reading music, but whenever I see examples of dotted rhythms/syncopation/just odd rhythmic groupings in general I get stuck and just give up on the piece.

I've looked online for books on rhythm/sites but they all seem to just breeze through the subject. Aside from hiring a music teacher, do any of you know any sites/books/ideas that would help me get through this problem?

Thanks
Break the piece down to its fundamentals, if the shortness note length is an eighth note, break it down to "1-and-2-and..", sixteenth note "1-ee-and-a-2-ee-and-a.." etc. Write the counting beneath the notes so you see how many fundamental beats each note/rest is held for. Syncopation can be tough for beginners but it's one of those things you'll just grasp eventually and have not much of a problem with afterwards.
I'm sure it's nothing we here on UG can't help you with.

What is it that you struggle with in regards to those rhythms?
Only play what you hear. If you don’t hear anything, don’t play anything.
-Chick Corea
Quote by NewShred
Break the piece down to its fundamentals, if the shortness note length is an eighth note, break it down to "1-and-2-and..", sixteenth note "1-ee-and-a-2-ee-and-a.." etc. Write the counting beneath the notes so you see how many fundamental beats each note/rest is held for. Syncopation can be tough for beginners but it's one of those things you'll just grasp eventually and have not much of a problem with afterwards.

I think this is a major part of my problem, I usually count the major beats, then just freeze when I see something I don't know how to handle.

One thing I absolutely don't know how to count though are notes grouped together (tied?). I can do basic triplets, but when they aren't all the same note, or you throw a dot in there, I have no clue how to count it.

I also ran into 22 8th notes grouped together in a measure of 6/4. How does that work exactly?
If there is a slur over a group of different notes, it is referring to phrasing, or more specifically to play the phrase in a legato manner. If connects two or more of the exact same note, it is a tie, which means to add the beat value of every note in the tie to the very first note. Make sure you only play the first note, when you see the same note tied to it make a conscious note to just keep holding down the original note and not to play it again. This is a technique composers use mostly to escape beat restraints on a certain bar, i.e: I have room for only 1 beat left in a certain bar, but wish the note to be held for 3, so I will wright a quarter note filling the bar, and tie it to a half note in the next bar.

As for your simple duple time question, was there a small number over the group of notes? I would imagine there was a quadruplet or quintuplet that you may have missed, as having that many number of notes grouped together in a single measure is unlikely.
It really is just a matter of keeping at it, and practicing it regularly. When you do encounted rhythmic values you've never seen before, it might take a while to get used to it, but after a while, you just start to recognise rhythmic groupings, and the way they sound.

I always found that when I saw a rhythmic grouping I'd never seen before, it was better to put my guitar down, write out the counting for it, and clap it to myself for a while. Then, when I'd go back to the music, it'd flow a lot more naturally.

Keep at it, and if you need help with how to count any rhythms, there's a lot of resources online, or you could just ask here. I'm sure someone would be able to help you out.
Not a huge fan of bees
Count. Subdivide as much as necessary for each note to be on a count.

Let's take an easy example: Dotted crotchet - quaver - dotted crotchet - quaver in 4/4 time.

I'm guessing you usually count 4/4 1 2 3 4. When counting like this the quavers don't come on any count. So subdivide every count into two. Now you are counting 1 & 2 & 3 & 4 &.

Now work out where the notes lie. The first dotted crotchet starts on the 1, obviously. The first quaver starts on the second &. The second dotted crotchet starts on the 3 and the final quaver starts on the fourth &.

So now you know where the notes fall, count very slowly and play as you are counting.

Once you can do this you can do any similar pattern (eg. dotted quaver, semiquaver). Once you get down to semiquavers you can either count 1 a and a 2 a and a... or just use the numbers for quavers instead 1 & 2 &...8 &.

Whever you can't get a dotted rhythm/syncopation just count and play it slowly. After a while you will internalize the sound of the rhythms and you won't have to subdivide, you'll just be able to play it (it's always a good idea to count something, even just 1 2 3 4).
When I read dotted notes I just count to 3 in my head.