You are unfortunately almost certainly wrong. Look at China - roughly 3,000 deaths, from roughly 100,000 cases (actually somewhat fewer). Their healthcare system is very good (as the WHO has said, they are very good at keeping people alive with this disease), so there's no reason to suspect that we'll do any better.
The government is expecting somewhere between 35% and 80% morbidity (penetration of the population) over the next 6 months or so for this disease [why won't we stop at 80,000 like China? Because we won't/can't/don't want to enact the draconian quarantine restrictions they have in order to contain this]; taking the lower end of this (and rounding down) is 20,000,000 cases, 200x that in China. There's no reason to assume we can get any with much fewer than 200x the deaths, or 600,000 people.
Or look at it another way - globally wherever there are enough cases to measure, about 5% of cases require hospital intensive care of some sort. One can assume that they are put into intensive care because there's a good chance they'll die if not - hospitals don't do this lightly. Let's say that 50% of ICU patients didn't actually need it (I think is probably a massive overestimate, but let's use it anyway, as a best case). Therefore 50% of those needing ICU care will die without it. 5% of our already optimistic 35% or 20,000,000 cases is 1,000,000 people. There are 4,000 ICU beds in the UK. Let's say (and this is now wildly optimistic) that somehow we manage to make that rise tenfold and a bit to 50,000 ICU beds. Let's further made this best best case and say those 1,000,000 ICU-needing cases are spread evenly over the 6 months (they won't be, they'll peak in the middle), and each one only needs it for 3 weeks (which is what the data show) - so 9 periods or so in 6 months. So we have in our hypothetical case here 9x50,000 ICU places, or 450,000, for the 1,000,000 that will need them. 550,000 people therefore won't get one, and we've decided that only 50% of those needed one to stay alive - therefore 275,000 dead. And there are several optimistic assumptions in that calculation.
If we get away with even just a few multiples of 17,000 dead just by the end of this year it will be a miracle.
The in-house isolation is not to protect YOU - you are unlikely to die as an individual - it's to stop you spreading it. People need to understand this point - it's a population risk problem, not an individual risk problem. Look at the numbers above. If we don't al work together to contain this they could easily be multiplied several times. It can be done - look at China - don't just look at your personal risk-reward (or risk-inconvenience).