Question: Can anyone describe differences between XR and regular...

Question: Can anyone describe differences between XR and regular, either from experience or medically speaking? I was diagnosed add and prescribed about 10 months ago. The adderall worked immediately, no significant side effects. I mentioned it wore off before I was ready. I was prescribed 30XR and 15XR twice a day. I feel a little different than before, i have anxiety I didn't have before. Also, I do feel like if I skip a day, I took Nyquil, and I can't do anything except sit around. Normal? is it the XR vs the normal? thanks for the comments