Child giggling early morning /late night

18 month old super cute toddler keeps a bit giggling before sleeping and early morning wake ups . No such incident noted during day . To be honest she has been having a rarely large amount of screen time Due to tough circumstances as her grandfather passed away and we could not give enough time to her as we both are working parents and all our remaining family stays away from us . The laughter also stops in case we divert her attention. We generally feed her dosa /cerelac /aalooo paranthas /daal /paneer /egg/etc She was formula fed (just as an input to for consultation ) She hasn't slept well for couple of nights due to disturbance in her sleep cycle it generally takes 4-5 days for her to be back once missed Also I was having bfast couple of days back and she was insisting on me to feed her the tang drink which I have with bfast so I gave her very small fake sips of it and she has grown fond of it .I haven't fed her but she likes to have a couple of dots of ketchup. Is it a reason?