Pressure on my head and feeling unbalanced when I walk. Any idea what this could be?

When I first woke up this morning, my head hurt so bad I could barely get out of bed. I managed to crawl out and drink some water and slowly walk around. Then I noticed I was feeling very unbalanced when I walked. I didn’t fall over though.
I have no other pain anywhere else on my body other than pressure on my head. It’s not a dull or sharp pain. Just a heavy feeling all around my head.
My unbalanced problem seems to be much better although still a little wobbly.
I realize only a doctor can diagnose me but anyone have ideas on what this could be?
I do plan on going to urgent care later today.
My bf has suggested dehydration.