It should be, as long as you can connect on time. The official servers are configured for maximum decay time of 168 hours, which is one week.
However… the devil’s in the details. I don’t know how much you know about how decay works in this game, so I apologize if I cover stuff that you already knew.
First of all, what we’re talking about here is the maximum decay time on the server. That doesn’t mean your base will necessarily have that decay. You can check what decay time your base has by wielding a repair hammer and standing close enough until a little popup comes up and it shows you the decay timer, the stability, and the structural health of what you’re looking at. If you’re on PC, you can also do that without a repair hammer, by holding the TAB key.
Here’s how decay timers work. Each building piece and placeable has a decay timer. (“Placeables” are things like crafting stations, doors, furniture, torches, etc.) The interconnected building pieces share the same decay timer. In other words, if you build one foundation and a wall on top of it, they’ll have the same timer, but if you build one foundation and run far enough away and build another foundation, they’ll have two separate timers. The placeables share the decay timer of the building they’re in or on. If you put a placeable down on the ground and it’s not within the claim of a building, its decay timer will be very short, and you’re likely to lose it eventually. I’ll explain more about that later.
Each decay timer has its maximum value – and I’ll explain soon how that’s calculated – and as long as you (or anyone in your clan) is close to a piece that has that timer, it will keep getting refreshed to that maximum value. So if you’re inside your base and its maximum decay timer is 56 hours, it will keep getting refreshed to 56 hours as long as you’re there, and will only start ticking down when you go far enough away or log off.
How is the decay timer calculated? Nobody outside Funcom has the exact formula, but we know that it depends on how many building pieces are interconnected and what tier they are. Sandstone and flotsam are the lowest tier, so they’ll have the shortest timers. The more interconnected pieces you have and the higher their tier, the longer the decay. The maximum decay time calculated by this function is further capped to the value set in the server settings. So maybe you built a big base and its decay timer would be 300 hours, but the server is configured to 168 hours maximum, so it will be 168 hours. This is important to understand, because of the summer vacation timer changes, which I’ll cover soon.
If the decay timer reaches 0, the building does not disappear right away. Instead, it enters “abandoned state”. The abandoned state lasts for 24 hours, and during that time any player can demolish your placeables individually or your whole building at once, by coming up to it and selecting the “demolish” option in the radial menu. So if your server is configured to 168 hours maximum and your building is big enough, it will have 168 hours before it enters abandoned state, and then 24 hours in that abandoned state. During those 24 hours, it will still be standing and you won’t lose anything unless another player demolishes it.
After the 24 hours of abandonment elapse, the building will be destroyed. However, the server does not do that proactively. If there’s no player in the vicinity of a building, the server does not simulate it. Instead, the server “catches up” when a player comes close enough. That’s why you’ll sometimes see a base disappear right before your eyes – it went through decay and abandonment, but there was no one there, so now the game went “oops, gotta take care of that” and poof! It’s gone.
Now, I mentioned summer vacations. Once a year, Funcom will reconfigure their official servers to double the decay timer for a couple of months, so the maximum decay for the server becomes 336 hours instead of 168. However, that doesn’t mean that the decay timers for the buildings are doubled. Remember what I said about the cap? If the decay timer function for your building says it will decay in 250 hours, that will get capped down to 168 hours under normal circumstances (because 168 < 250), but you won’t get 336 hours during summer vacations, because the function evaluates it to 250 hours and then it doesn’t get capped anymore (because 336 > 250).
I know the above paragraph has nothing to do with your situation right now, but I wanted to explain that anyway, because many people make the mistake of assuming their base will have 336 hours instead of 168 and then they lose their stuff because they didn’t check 
Okay, I think I’ve covered the most important facts here. There’s more stuff to learn about the decay, but I won’t go into that here. I apologize for the wall of text, but I’m hoping this will be useful.
In short: you need to check what’s the maximum decay timer for your base specifically. If it says 168 hours, you should be fine (unless you run into one of the decay bugs) if you can log back in on time. And even if you don’t, you can still hope that no one will demolish your base while it’s abandoned.