I've seen some people get freaked out every time a car or truck passes them. Some folks aren't used to riding with other traffic, and I can sympathize. I recommend a course of acclimatization for those people.
First, get used to riding on quiet suburban streets (or deserted rural roads) when there's almost no other traffic -- think Sunday morning at 7-8:00. After you're used to that, graduate to lightly used streets or roads -- perhaps a car every minute or so. Learn to hold your line (meaning you can't dodge between parked cars!), and they'll have to go around you. Next, look for a four lane street you can ride at a time when two lanes would carry all the traffic. (In these Covid times, that may be near schools or in small business districts about 9:00 weekdays.) Again, ride that kind of street until you're comfortable with it. Next, try riding the same streets when school's out, or around lunch time. You may start to get some honks or yelling from people who really don't know how to drive, or that you're legally allowed to be there; as long as you're riding straight, holding your line, you should be OK -- they don't really want to have to stop for 30-45 minutes to deal with a cop. Deal with it. Once you're comfortable with that, you can handle riding almost any road, any time. (An exception might be a road you really don't want to be on, a highly trafficed, high speed road with no shoulders, for instance. Just stay off those as much as possible.)