My DD is 17weeks and recently started crying at bed time when we put here down. We presumed that she is overtired and have tried putting her down a bit earlier but it doesnt seem to help. She seems frustrated and trying to suck her thumb to soothe herself. She can work herself into quite a state. I found that a drop of lavender oil on the sheet worked but dont want to rely on that. I know that there is often an age window in which to deal with certain behaviour and dont want to miss this one but also dont want to be too strict and start the dreaded controlled crying if she is too young and just needs cuddles. Any advice?