The symptoms of internet addiction can vary but often include:

Preoccupation and lack of Control: Constantly thinking about being online and being preoccupied with thoughts of connecting online is a sign of internet addiction. In addition to this a person may also find difficulty in controlling the amount of time spent online or repeatedly fail in cutting down internet use despite conscious efforts.

Neglect of Responsibilities: Neglecting work, school, household chores, or other important obligations in favor of internet use is another sign.

Disconnect anxiety or uncommon behavior:  Feeling irritable, restless, or anxious when unable to access the internet, this is akin to withdrawal symptoms as seen in substance addictions. It is basically the discomfort experienced when disconnected from internet or online world.

Social isolation and escaping Reality:  Getting addicted to internet can induce a person to prefer online interactions over real-world relationships, leading to social withdrawal and isolation. The online world or Internet may be used as a way to escape from problems, stress, or negative emotions which may lead to addiction.

Increased thresholds for gratification:  A person addicted to internet may slowly notice rise in need to spend increasing amounts of time online to achieve the desired level of satisfaction or engagement.

Impact on overall health and daily life: As a person gets increasingly engaged with internet and online world, they can experience negative impacts on mental and physical health.  It also interferes with their daily schedule, self-grooming, work performance, academic performance, relationships, etc., 

Loss of Interest:  Decreased or loss of interest in other activities that were once enjoyable or fulfilling, like hobbies, sports, social interaction, etc., that were once enjoyable in favor of online pursuits.

It's important to note that experiencing a few of these symptoms doesn't necessarily indicate internet addiction, but a combination of these symptoms over an extended period may warrant concern and potentially require professional intervention or support.