Baby sleep help please!

My daughter started sleeping 10-12 hours at night around 2.5/3 months old but then stopped around 4 months. She's 6 months now & wakes up Every. Hour. Nothing has changed in her bedtime routine apart from her dad sitting in during bath time but I don't think that could be it? I've been trying to break the habit of nursing to sleep the last 2 nights but it doesn't seem to be helping.

I desperately need sleep and I need to fix this soon as I'm going back to work in a week. Any tips?