Anxiety as a medical condition is really beyond the scope of an astronomy forum. This is the wrong place to come for advice and this is the wrong place to give it.
A nervousness about having an interaction with a ranger, police officer or property owner is understandable but the chance of a bad encounter is vanishingly small. If you are violating some public access rule such as park closing time, you are at most going to be asked to leave. If you are inadvertently on private land that is not posted, you will be asked to leave. AFAIK trespass law in the US treats it as innocent trespass for which you cannot be arrested. If you are shot your estate will collect handsomely.
Wild animal attacks at night or at any time can and do happen but they are very rare (allowing for those caused by people feeding the bears or taking a selfie with a moose or Bison).
Assaults by crazed humans are likewise rare. Most murders and rapes are very close to home. Robbery requires us to imagine that a robber is lying in wait or searching for victims in parks and dark site. Again not something you see in the news very often and on the rare occasion when you do the victim is not out with a telescope.
I have seen or heard fearsome animals in the moonless dark, bears, racoons, possums, skunks (kits very cute), turkeys, owls, and coyotes, the deadly scorpion and two teenagers whining disappointment at finding an old fart with a scope in their favorite parking spot. Once at a distance the truly blood curling sound of music and chanting from the devotees of some philosophical ideal.
But we are by nature afraid of the dark, some say. Really and do you fear heights because our antecedents includes tree dwellers? Humans can see usefully at night. Astronomy takes place on clear nights and on clear nights most of us can see fairly well, even after middle age arrives. Once your eyes are dark adapted you can see that bear contemplating a meal. Not you, the snack you brought.
Have we become a nation of men (mostly) that have not been in the Boy Scouts, the military or sat under the stars after a day of backpacking? Maybe we have, but the cure is a night under the stars and FDR's famous line about fear.
Stand tall, grab your gear and head out. You will live to tell the tale.