I live in Lisbon. Without knowing anything about where you're coming from, how long you plan to stay, whether you're in an at-risk group, your vaccination status, whether you've caught the virus and recovered etc, it's a bit difficult to give solid advice, but in general, yes, I would suggest holding off.
The current situation is that despite being one of the three most vaccinated countries in the world, today Portugal set a record for positive cases (65,000 in 24 hours, in a country with 10 million people). It has averaged over 50,000 each day for over a week now.
We know that Omicron is more contagious but less severe than previous variants and that case numbers by themselves are not the be all and end all. If you come here and catch the virus, it's possible that you may only get a little sick or not sick at all. But for travel logistics, Omicron is very problematic because regulations haven't really adjusted to it. If you catch the virus, you'll have to isolate and that's going to be complicated in a foreign country and may also hinder your departure.
No one knows what will happen in the future but the virus does come in waves so if you could hold off for, say, two months until this wave recedes, the situation might be better.