HELP!! Seperation anxiety during night!

My LO has been in her own crib and room since we brought her home. She has been usually an excellent sleeper, expect during teething and growth spurts. She turns one next week and has developed seperation anxiety during the night. She goes to bed around 7/730 every night, gets breastfed and laid down in crib (sometimes sleeping or awake). She will then sleep for about 2 to 3 hours and wake up crying. Sometimes I can get her back down, but on other nights, not so much. On the difficult nights, she will be fed, changed, given her stuffed giraffe and soothed. She will be fine when we are in the room but immediately cries once we leave and won't stop till we return. My husband is going out of town for business in a few weeks for 3 nights. I hope she is back to her normal sleep pattern by then, but who knows. Looking for help, so we can all get back to good sleep