Bedtime scaries 🥶

The past 2 nights our normally easy to put down baby has been fighting bedtime tooth and nail. She will go down initially after her normal bedtime routine, but then wakes 30 minutes later and screams for 2+ hours no matter what my husband and I do - leave her in crib and rub her belly, rock her, even nursing doesn’t help. Last night she woke pretty much every 2 hours after that as well and was tricky (tho not 2+ hours) to put back down as well. Daughter is 18 weeks - Is this all part of the dreaded 4 month sleep regression? Do I need to implement new techniques (self soothing and SIT BACK for those of you who use takingcarababies) for this to pass or will she learn to connect her sleep cycles on her own?