I have not taken Ritalin, but I am currently on Adderall which I believe works similarly. I was nervous about going on Adderall as well. Just the idea of taking a medication that effected my brain was unsettling and I was afraid it would make me feel weird. What I did to cope was start small. My doctor first prescribed me 10mg twice a day. I cut them in half and started with 5mg for about a week before moving to 10mg. Same when the dose was increased to 20mg. I started at 15mg for a week and then increased to 20mg.
In the end, I dont feel anything physically different when I take my medication (except for managing my ADHD), it was just in my head to even be worried. If you are concerned about side effects, I havent had any except for loss of apetite, but that wore off after about three weeks once I found the right dose.
Hope this helps! Im sure you will be much happier and feel more in control once you start the medicine. It has made a huge positive difference in my life.
I thought Ritalin came in strengths of 5 or 10mg and Only lasts 4 hours so I don't see it interfing with sleep. However, Concerta which is a longer lasting Ritalin lasts up to 12 hours which would interfer with sleep if you are not taking it early enough in the morning. The other issue is it takes a couple of weeks for some side effects to where off. I think if you found the correct medication for your body you would be amazed with the results. Good Luck!