Get as much rest as you can, your body will let you know what rest it needs. Hormonal changes in your body contribute greatly to exhaustion. If this is not your first child, consider having someone look after your other children for a few hours so you can catch a much needed nap. Sometimes low blood sugar can cause dizziness or even the growing uterus can be placing pressure on the arteries. Acne - Changes in hormonal levels in your body can change the type of skin you have.
Oily skin can become dry, dry skin can become oily.
Use a good cleanser and moisturizer to try and minimize these effects. No wonder you are a little irritable. Again, hormonal levels that are increasing in your body, will affect this too. Retaining fluids during pregnancy is more common later in the pregnancy, but can begin in the first trimester. Consult your physician if your face or hands appear swollen.