Hugs
If it's not a BP or hydration issue, think it might be tension headaches. 16wk and have been getting those quite frequently. I see an LMP to release that area, but if you can't do that get your partner or a friend to help.
Lie on your back, have the person rub from your top thoracic up your cervical spine in long motions lifting your head a little bit. This will release the muscles in your back.
Next have them press the pads of their fingers into the space between your neck and head. If there is a lot of gunk there it will be kind of sensitive. Switch between rubbing the spine and pressing into your head. The area is all the way between the ears on the back side of the head where skull meets spine
Rub gentle circles with fingers from back of head up over to the front and sides.
I hope this helps you!