Not sleeping

I am at my wits end with my 6.5 month old. She is refusing to sleep all of a sudden. Since her 4 month sleep regression she hasnt slept great but now she will only sleep about 45 minutes at a time and cries if I put her down. Not to mention the hour to 2 hour stretch of awake time in the middle of the night. I'm exhausted and my husband is no help. I asked him today after her 30 minute nap to take her and all he did was play with her on the bed so I couldn't go back to sleep. I can't do this anymore but I dont know what to do to change it! Any suggestions would he wonderful.

Yes, she is teething, but has been for the last 3 months so who knows when these teeth will appear. And she won't let me do any kind of gentle sleep training without crying hysterically until I let her nurse. She won't even let me sleep during the day either. I have to be holding her while she sleeps so I can't get any sleep that way.