Trying to quit Sertraline

Hi, I've been on Sertraline 50mg for about a year and a half. I no longer feel like I need it but unfortunately can't get into my GP until August. I am currently cutting my tablet in half to 25mg and plan to do that until I go to my appointment.

Any ideas on how I can minimise the side effects? I currently feel sick and dizzy, yesterday I felt irritable and I'm just not feeling too great, is there anything to make the process a little bit easier?