i used to get really paranoid as well when i smoked, and what i discovered helps is a change in my smoking mechanics

when i first started smoking i used to always try to take the biggest possible hits i could possibly hold. this would give me an intense high quickly, (probably partially from lack of oxygen), which would often be edgy, paranoid, and unenjoyable, and then it would fade much quicker.

now i breath as slowly as possible when taking a hit and take moderate-small sized hits, sort of like sipping at wine, which not only conserves weed, but lets you fully taste the weed and enjoy the smoke. i feel like this way i get a much more sustained high with an enjoyable come up and come down, and i feel like i get all the full effects of smoking rather then just a quick burst and crash like a cigarette