Astral projection may be newer territory for you, idk. I am still afraid of my mediumship and sometimes astral projection., They seem to go hand in hand since I work with uncrossed spirits, I'm always afraid that they will try to take over me when I'm gone. I haven't gotten over the fear so I decided not to go into a really deep trance. Instead , in a spiritual sense, I stay mostly conscious within a light trance so that way I can still be somewhat aware of what is going on around me. It's just as effective for me. Alot of my fears stemmed from childhood experiences with spirits and the supernatural. What I would suggest is to figure out what your fear is. Don't dismiss it as little because it's a legitmate fear because you fear it Acknowledge it and if you can't completely get over your fear, compromise with it. Find a way to meditate that will let you feel more comfortable astral projecting. perhaps you are afraid of what will happen if you leave, if this is the case, be clear about where you want to travel and set the intention or purpose of your journey before you go. Ask your guide or angels to travel with you and add a protective shield around your body and an archangel to protect it while your gone. Maybe you are afraid of not having more control if this is the case, try going into a light trance and stay earthbound. Maybe your afraid you won't return, if so, invision a cord connecting your soul to your body and set an alarm for the time you want to come back, ect.
You could also do a ritual cleansing before and after to prevent hitchhikers. Because your afraid of that spiritual realm, create a space that you are confident you are protected in and this should help. If your fear, however is stronger then your desire, you may want to confront that fear and go further on what the fear is and why you have it. Hope this helps,