Hi Startnovr, first thing is to take care of yourself, at least one hot meal a day, exercise etc.
Next, try and claim the dole. While you may be not be able to claim Job Seekers Benefit, you might be able to claim Job Seekers Allowance. Call in to your local Citizens Information Centre and ask for advice on claiming everything possible, medical card, rent allowance, everything. You have to take care of yourself. Also, be looking for work and somewhere new to live.
Once you have an income, and somewhere to live, then it's time to sort out the Revenue. Not filing tax returns can result in a criminal prosecution. So the thing to do is to file the tax returns, without making payment, and a few weeks later apply for bankruptcy. Assuming of course that you are unable to make arrangements to pay the outstanding tax, interest etc. Maybe your tax liability is less than you think, and you are worrying needlessly. Might be an idea to engage an accountant to work it all out for you. But first things first. An income and somewhere to live. Best wishes.