Abstaining cravings during pregnany

Is it okay to abstain from cravings during pregnancy? I've been trying really hard to abstain from my cravings but I can't seem to stop thinking about my cravings every day. I salivate a lot and it feels really bad to consume food that I know is beneficial for me, but at the same time not what I really want at the moment. I've been avoiding spicy and sweet foods for a few months now and I feel like I'm reaching my limit.. Do you give in to your own cravings, or were you able to avoid eating foods that are not good for you such as sweets and fast food?