Where I agree with Krnshetty is where they tell you not to worry about the vibrations, you do need to stay focused. However keep in mind you also need to relax.
The fact that you're feeling sensations like the vibrating and the dizziness means you're incredibly close. In actuality that dizziness is probably caused by a disturbance with your subtle consciousness.
This brings to mind a few things you might want to try...
First of all, I read this issue of yours and immediately of blockage. Try a cleansing bath for your body's energy. The warm water will sooth you as well.
Second, try grounding. It's good to have yourself centered and at ease when trying to make that split from your physical body. The more relaxed you are mentally and physically, the easier astral projection will be.
Third, make sure you meditate on into your method of projection. Not everyone has to do this but it can help some of the more difficult cases. To be more clear, I mean you should meditate either just before or as you're attempting to project (if you don't already).
From there I can elaborate more on blockages. Blockage in your body's energy can work likes extra weights attached to your subconscious or subtleties. You need to make sure your internal energy is flowing smoothly through out your body. If you do, it will prove much easier.
Small blockages can usually be fixed by meditating, grounding, centering, cleansing, basic chakra work, etc...take your pick.
You want to make sure you're eating healthy and getting plenty of rest. I wouldn't suggest attempting projection where you could easily be disturbed (especially if you don't enjoy that dizzy feeling). Stay focused and be patient, success comes with practice.