Waiting 28 weeks for a sonogram????

My doctor is so annoying. She only allows a sonogram at 8 weeks (which shows nothing but a lump of flesh), then she drags it out for one last one at 28 weeks. Isn't that an abnormally long wait for a second sonogram?? I'm currently 23 weeks and I'm dying. I want to know if the baby is developing well (organs, etc.) and the wait is making me totally mental.