Coffee makes you sleepy?

[Sweetthicthighs]

I've drank coffee since having babies 11 year ago I started and lately I'd say in the last few year every morning I drink coffee I'm instantly fatigued, what even is that? Coffee just has no affect on me, I'm not woken up I'm fatigued for the whole of the day!.

I am thinking of switching to a cuppa tea instead I'm also on the "is it my B12, is that low" thought too. I'm only 33 so I doubt I should be feeling like this, any thoughts?