I'm pretty late to respond but I feel like I have to. It's interseting how similar your situation is to mine before I was diagnosed with GAD. Now, I'm not saying that you do because my anxiety started when my older sister started running away and later died. I was an A student but suddenly I became less motivated in school, I was slowly arriving to school later and later. I didn't want to stay in school so I would leave early. I was unable to sleep during the night but woke up early in the morning and started counting down until my alarm rang and became more terrified with every growing moment. You may or may not have GAD but you did say you were stressed, it maybe school or something else so going to see a therapist won't do you any harm.
If your still a bit curious or just want someone to talk to message me. I'm more than willing to talk.