what do you do about being followed?

I feel like the police won't help because they never take things like this seriously, but there is a blue van that is constantly parked outside everywhere I go

Last night I had a drink at the pub and the thing was parked right outside, I walk home and see it on the way back and when I get home it was there again. I never see anyone in it and on the two occasions I walked up to it I saw nothing in there. Once when I was at the hospital I could see it from my room but it was facing away from me. It drove of. The van isn't registered when I look it up on various apps/databases. it has no decals, nothing. It looks like it is being rented, it has literally no information that I can see through the window, no letters, no tax discs, nothing

I went to a town that is 13 miles from my house and there it was, yet again. I feel like something weird is going on, what do I do?