Dizziness often comes during 17th week in second trimester. It's due to the hormones, your growing uterus and a rapidly expanding circulatory system.

Meanwhile your little one is learning how to suck and swallow and they have also started to develop fingerprints.

Your baby has grown and your little one weighs about 5 or more ounces and is the size of your palm or around 5 inches long. Baby's body fat starts to begin forming and will continue to accumulate through the end of your pregnancy. 

Baby's practicing sucking and swallowing

As practise makes one perfect, your baby is sharpening their sucking and swallowing skills in preps for that first, second and third suckle.

Most of the survival reflexes your baby will have at birth are being perfected in utero now.

Fingerprints are forming

Within the next few weeks or so, the pads on your baby's fingertips and toes will be with individual swirls and creases which are the fingerprints.

Fetal cardiac activity is more regular

Your baby's heart is now being regulated by the brain, so no more random beats, and is churning out 140 to 150 bears per minute which is about twice as fast as yours.

Source: https://www.whattoexpect.com/pregnancy/week-by-week/week-17.aspx