Is it normal to feel spaced out after taking Vyvanse?

I got diagnosed recently, and have now started taking Vyvanse. I got started on 30mg, and I took it for the first time today.

It's now been around 2 hours since I took it (with protein), and I feel calm for the first time in my life, so that's great. But It's almost like I feel TOO calm. My brain is fuzzy, and I feel spaced out, which is making it hard to do my work.

I also stopped drinking coffee abruptly just yesterday, which I was drinking a lot of for a long time, over 300mg a day.

Is this something that happens at the start, or is the dose too high for me, or could it be caffeine withdrawals?