Why cant i sleep!?

Today is friday at 11:23 pm .

On thursday i woke up at 9am. I was up all day and took 10 mg of melatonin ( which i do on occasion if im having issues slowing down, and went to bed around 11pm. I laid there till 6am on friday. Didnt sleep. Got up, showered, went to the store, had a short 930 am - 11am nap, went to the bigger close city with my fiance and went to my grandmothers to sleep from 1230 - 2 while she watched my baby daughter. Got home after running errands at around 7, pit baby to bed, ate a bit, laid down exhausted, couldnt sleep. I finally took a double dose of zzquil. 60 ml, which ive never ever done, ive only taken zzquil twice. I took it 1030pm. Its 11:28pm now on friday and i still cant sleep. Ive never had this much of a problem sleeping. Im able to clear my mind, im exhausted. Why am i just laying here not able to sleep?