I can't sleep. Even if I go to bed at 8 I wake @ 12. up till 3 or 4. Wake at 6.Melatonin not working. Can I take sleep aid as well? Other suggestions?

Can't sleep. Talk to your doctor about this to see if you need assessed for secondary insomnia (insomnia due to other organic or psychological factors) which can be treated. Meanwhile you can try the sleep hygiene techniques. Google those words for details.
Experts say... Sleep in pregnancy is important! Here's advice. http://www.sleepfoundation.org/article/ask-the-expert/sleep-hygiene when a 1st choice drug is not effective, it often means that there are some things you can do on your own or with a sleep clinic workup and treatment plan. Solving problems can be like solving a mystery - keep hunting for the real problem. Good luck!