My 1 year old crying panting

My 1 year old female dog suddenly one night was crying and then kept crying throughout the day, then continued for the past 3 days but at random times and was pooping perfectly, peeing perfectly and also was able to play. Recently, for the past 2 days she has this one toy that she now brings everywhere and cries with it. At night she starts panting, and whining but when I’m in bed she gets very close to me, like very close and I pat her and she sleeps well and stops crying or panting. It’s very unusual because she wasn’t like this before, but now she keeps panting and bringing this one toy everywhere hiding it, she also hides sometimes. Why? We went to the vet and did blood work test and it all turned out well.