Weening toddler off melatonin

My best friend recommended this alll natural cough and mucus medicine to me when my two year old was really sick with a cold and she said it would also help her sleep better. the bottle said 2 years and up and my daughter is 2 years and six months and my father in law who is a doctor said it would be great. i gave her some every night for 2 weeks until her cold finally went away. but now she won’t sleep well at all. she’s waking up in the night and her naps are messed up. i feel so awful i got her body reliant on melatonin. i should of done more research on what that is. Should i just caught her off cold turkey like i have been or should i ween her off? I don’t need any “mommy-bashing” cause i already feel so so bad. Thank you ❤️