Update:
Thank you for your responses! Last week I woke up one morning very sore but I hadn't done any exercise that would make me feel this way the day before. I felt like I had, had a full body work out. Lately I've been really thirsty and I don't know if these are related. But I do think I will ask my parents to take me to a doctor.
Hello and hope you are doing well.
Shuddering or restless in sleep could be due a sleep disorder. These disorders can be like obstructive sleep apnea, wherein during sleep there is an obstruction to air flow due to laxity of the throat muscles during sleep and this could cause restlessness. Hence for therapy CPAP (continuous positive airway pressure) is used to keep it patent. Another cause could be an entity called restless leg syndrome, where there is an odd sensation in the legs during sleep causing the individual to move, which relieves the sensation. These disorders can cause inadequate sleep leading to fatigue and daytime sleepiness. So, I would advise you to consult your primary care physician for further evaluation. He may then ask for a sleep study called polysomnography for further evaluation.
Hope this helped and do keep us posted.
If you're still waking up feeling unrested you should see a Dr. A GP can order a sleep study done. For this study they basically hook you up over night to monitor your Oxygen/CO2 and heart rate. I think this could be beneficial to you and at the least will rule out sleep apnea.
Also is your oxygen issues related to asthma or allergies? You may want to consider talking with your parents to get a filter in your room. And if either of them smoke make sure they do it far from you, because it could be causing you problems.