Hi

my 3month old DD has had a huge decrease in appetite.
She used to be such a hearty feeder, she'd feed so much that she would spit up every single time. Now she has zero interest. If I do get her to latch, she spends the whole time coming on and off and staring at her surroundings.
Usually, she squirms and cries as soon as I try to get her in position, but then often will latch on the other side, but only for a moment, and then it's just wide eyed looking around again.
Even with this decreased intake, she doesn't seem to notice. She is even sleeping much longer at nights. I haven't weighed her yet, but I'm really quite sure that she feels noticeably lighter. Her weight gain normally rockets up.
She seems like she's thriving though, she's quite happy all the time.
Is this normal 3month old behaviour?
Should I try to force her to feed, and just keep trying till I'm sure she's had enough?