Thank you very much for all the advice everyone. I was in the process of putting it into action when something disastrous happened. Something that most people here expected I would imagine.
The following is an account of the day my first proper fortress fell. I don't want to bore any of you with a massive story so I'll summarize as much as possible. NOTE: If you don't want to read what happened, I have a few questions at the bottom.
Ok, everything was going quite well. I had my miners do some exploratory mining and found a cavern with some nice gems in it. I started making bone bolts, put my war dogs in a pasture by my fortress entrance outside, built some traps and started making more leather armour. But alas it was too little, too late.
An Elf caravan arrived and I thought "great, now I can finally get metal". Just then, a Goblin siege started (my first ever siege I might add). 14 Goblin Crossbowman and a Pikeman all wearing troll fur and copper armour came onto the map right behind the Elf caravan. The Goblins quickly killed 2 Elf merchants and a Fisherdwarf and Hunter who were outside at the time. I then stationed my military squad (who were still melee fighters) outside my fortress to try and intercept the Goblins and my war dogs were ready aswell.
But to no avail. In a hail of crossbow bolts, all 5 of my war dogs, 10 other animals and 2 of my military squad were all dead. I then tried to attack the Goblins with my remaining squad members. However, the Goblins armour kept defecting the blows from my squads meager wood weapons. A further 3 of my squad were killed. Meanwhile, other dwarves from inside the fortress had started pouring outside to perform their apparently much loved hauling duties. They were quickly struck down one after the other by the Goblins, it was a bloodbath. It all happened so fast.
By this time, my squad had killed 4 of the Goblins and one had fallen victim to a cage trap. However, my squad was now down to a single member, the rest had died gloriously in battle. At this point, the remaining Goblins retreated and the siege was over.
The final death toll: 25 dwarves, 5 war dogs, 10 assorted animals and 2 Elf merchants. However, the worst was yet to come and it was something that would ultimately destroy my fortress...
Right after the siege had ended, lots of dwarves became miserable and started canceling their duties to throw tantrums instead. This was probably due to the hugely traumatic experience my poor dwarves had to endure a few moments before. What happened next could only be described (according to the wiki) as a "tantrum spiral" and I was powerless to do anything about it.
A few dwarves went stark raving mad and my Expedition Leader decides it would be a good idea to hack a Brewer in the right arm with a Copper Battle Axe (gotten from a trade), opening up an artery. My Broker then throws a pair of Sheep Leather Trousers at a Milker (lol) and bruises his leg.
It was all downhill from there. More dwarves start throwing tantrums and start destroying furniture. A Potter goes berserk and attacks a Wax Worker. Little did the Potter know that the Wax Worker was somehow wielding a Steel Battle Axe. The Wax Worker promptly strikes the Potter in the head with it, killing him instantly.
A Brewer goes berserk and attacks the same Wax Worker and quickly shares the same fate as the Potter before him. A few dwarves become stricken with meloncholy and subsequently die of thirst. A Mechanic is attacked and bleeds to death from his injuries a few moments later. A few more dwarves are then killed due to more in-fighting.
Then theres a Miasma outbreak in the Dining Room and another near the Tanner's Shop due to all of the rotting dwarf corpses everywhere. 3 more dwarves are killed.
More dwarves throw tantrums, more go insane and 2 more are killed. The 2-3 seperate Miasma outbreaks continue unabated. At this point I decide there is no point in watching the total chaos and utter carnage any longer and with a heavy heart I declare my fortress and its people unrecoverable. To be honest, it was probably doomed as soon as the siege was over.
And that's how my fortress came to a horrible, bloody end. My apologies if I went on for too long. But this is the first time I have experienced that aspect of the game and it was very interesting.
Now for a few questions:
How can I make my dwarves go/stay in the fortress during a siege?
Is there a way to recover from a tantrum spiral?
I looked at my bolts on the Stocks screen and found that some types of bolt were being forbidden seemingly automatically. Why is this?
Thanks in advance.