Caffine withdrawal ?

So I’ve stopped drinking caffeine due to my doctors orders. Haven’t had caffeine in maybe 1.5 weeks. Today I had an iced coffee on my lunch because I was so tired at work. I got a venti, but with soy milk. I felt fine afterwards but now I’m feeling irritable, and kind of anxious. Can that be withdrawal or my body coming down from the caffeine? I’m not used to this.