Hi there Maartje,
Remember to post the essay task as well as your essay so that we can make sure that your arguments are relevant. Does the task specifically ask for your opinion on the Internet's effect on people's social life? Or is it more just positives and negatives of the internet?
You are not too far away from a band 7 but you need to correct a few issues here relating to vocabulary, grammar and essay organisation.
Let's talk about vocab/grammar first. There are a few errors that you need to correct for. I will highlight some examples:
'I will notify the...' should be 'I will illustrate/highlight/describe/demonstrate the...'
'to people('s) social live(s)' Pay attention to singular and plural nouns.
'Surprisingly, (the) internet...' Use 'the' before 'internet'
'(a) health professional
'Professional healthcare use(s)...'
You repeatedly use the 'patience' instead of the correct word 'patient'.
As for your essay organisation, your first body paragraph talks specifically about the effect of the internet on health. If this is true, the paragraph should begin with a topic sentence that explains this: 'The internet has bought numerous positive changes to the ways that we look after our health.' Instead, your topic sentence is 'Surprisingly, internet has rapidly changed modern society to such an extend that we can’t live without it comfortably anymore.' which is a repeat of your first introduction sentence. The sentence 'The internet has bought numerous positive changes such as the information it provides and the way we communicate.' is not really supported since you only talk about effects on health, rather than information and communication in general.
You second body paragraph is more succinct and your conclusion is good, although this clause 'positive changes make our lives better' doesn't really communicate any information so doesn't need to be included. I think your suggestion at the end is also too simplistic - you write 'have a conversation with anybody you possibly can meet' which is very difficult to do since you can possibly meet thousands of people when you go outside. Something like 'It is important for our mental health that when we go outside we make an effort to build real connections with the people we meet.'
Keep working. Keep your essay organised and make sure that you fulfill the promises you make in your thesis statement and topic sentences.