I also have problems with rhythm. I have played for a time by myself, but in the end I returned to the same point: finding a good teacher, a good coach.
There are music topics which can be learnt like in English, Literature, Maths, Physics, etc.
However, there are other parts in music which are more abstract and can only be learnt with someone who can show you the right path like body movement, with just feeling, not thinking, making a good balance between reason and emotions.
That is where you need to find someone who can show you the right way to listen, sing and play music, someone who can help you remember how to perceive and feel music (I say it because in kindergarten, I suppose, we learn it before we go to a more systematize process where music is taught in a same or similar way subjects like Math, Science, Physics, English are taught, or undervaluated).
Maybe you don't want a teacher in this moment, so try to go to dance classes, they can help you with the rhythm issue. I am thinking, once I have enough time, on going to aerobics or dance classes (or in Blu Ray or DVD), where they use music and you move based on how the music is.