early sign of mania or overthinking it?

I couldn't sleep until 4am last night and got 5hrs of sleep and woke up without an alarm. I don't feel tired. I usually sleep around 9-10 hours. I am scared this is the first sign of mania, and I think the anxiety it's causing is reading as mania and making that fear worse. You can see the cycle here. My only other noticeable symptoms were being really frustrated at a friend last night while trying to fall asleep, music being especially enjoyable, and a thought in the back of my mind that maybe mania wouldn't be so bad. College is starting back up next week and I'm really worried this will mess things up. I don't know what else to do but rant to internet strangers about it.