Stressed out means burnt out or burnout. Being stressed-out means you have alot of stressors and your are not able to deal with all the pressure. Your coping skills and resources are not adequate enough to deal with all the stressors your are facing. And if this goes on for a long time, then there is only so much you can take- so you get stressed out or burnt out. Stressors can include burdens such as relationship problems, job problems, financial problems, and school problems, just to name a few.
When you are stressed out, you can have irritability, anxiety, depression, poor sleep, poor concentration, tiredness, poor appetite, and social isolation. When you are stressed out or burnt out, you may also meet criteria for an adjustment disorder. However, if you continue to have stressors and you do not address your symptoms of burnout, then you may go on to develop a more severe problem, such as depression or anxiety.