Donating Blood

I have never donated blood before and my work always has blood donation opportunities. So I signed up a few weeks to donate tomorrow morning. However, last week I scheduled an appointment with a psychiatrist and am going back on antidepressants. She prescribed me Trintellix and one of the side effects is nausea and it's really hitting me. My psychiatrist said the side affects could last a few weeks. I'm nervous to donate now because I always here when you donate blood it can make you feel nauseous, dizzy and lightheaded. I'm already feeling all those things with the side effects of my medication and don't particularly want to make them more substantial. What have your experiences been with donating blood? I'm contemplating if it's best to wait and donate next time once I'm stable on my medication and the side effects have passed. Any feedback would be appreciated.