It can be a number of situations. It may not be for you. It may not be real lavender essential oil. It may be cut lavender oil. Not to mention there are two different types of lavender, actually more but the main ones are Lavendula angustifolium and lavendula latifolia. The latter not working the same as the angustifolium. Many companies use a fragrance not an essential oil. In which case it will do no good.
Wanderingherb