Thorbbing In Head Upon Standing

Hey guys, me again. My anxiety attacks have almost stopped, still there pretty bad on occasion though, but now I have a new thing to fret over... Sometimes when I stand up, it feels like the back of my head is going to explode, not pain, just tightness. I'm guessing this is tension headache, seeing as I look at a computer screen almost all day. But just to make sure, can anyone back this up? It happens when you stand up, not necessarily a blackout spell, just a tightness in the neck/back of head. Thanks :(