The police won't come and harass you just for looking up things on the internet. If you've said or done something that really worried a family member or someone else in a position to know you, it's possible that they'd call the police and ask them to do a welfare check on you.
Since you mention the Samaritans I assume you're in the UK, which is not where I'm from. Are there any organizations over there that explain exactly what police can require you to do, and what they can't? Like if they want to come into your house and look around, or if they ask you to unlock your phone so they can see what's on it, are you required to let them? You might feel less anxious about the possibility of a welfare check if you knew what your rights as a citizen are.