Your belly button will pop!
The hormone Relaxin is at play now and will loosen your ligaments (which in your pelvis.. is necessary for the baby to be able to come out), however, ALL your ligaments are affected, some ladies find that their shoe size even increases because of slightly more space between their bones.
Your growing uterus is starting to take over your abdominal cavity, causing heartburn, try drinking before or after meals instead of with them so as not to aggravate the situation.

Your baby is now the size of a...
Coconut (10.9 inches long)!
By now, the baby is hearing some of the world around him, can hear your voice and your heartbeat hears your tummy rumbling and your blood flow whooshing around your body. His brain and senses are developing right now, and he will start to move his hands around and gently start touching his face and will try out sucking his thumb.
He now knows when it's light and when its dark, and you may find that if you lay in a warm bath, with the bathroom lights on.. baby will be alert and moving around.
Pregnancy symptoms at 22 weeks
Stretch marks, vaginal discharge, backaches, hair growth (yikes!), increased sex drive and an outie belly button. A pregnant woman's belly button pops due to pressure from her expanding uterus and stretching of the skin.
Don't worry, your belly button will go back in post birth.
Tips and advice for pregnancy at 22 weeks
Bear in mind that you must drink around 8 glasses of water a day to keep your circulation working, your blood vessels are under the same pressure because of your expanding uterus, you don’t want to end up dizzy or light headed.