For some women, hemorrhoids are just in the cards. (Sorry!) Ease the pain with creams, suppositories, hot or cold packs (experiment to see what works best), witch hazel pads, and sitz baths (soaking the area in a little hot water).
If constipation is the big issue, talk to your doctor about stool softeners. Then, once you've found a bit of relief, rest easy with the knowledge that hemorrhoids tend to ease up and disappear as your body returns to normal after delivery.