Hi Gina, if your house has developed a series of cracks all of a sudden, it suggests something potentially serious has occurred; like a loss of stability. You need to know what risk there is of 'catastrophic failure' and the threat to life and limb, by establishing the cause;- your insurance may not cover everything, but you need to protect your asset. Notifying your insurers at the earliest opportunity is important.
Have any works been carried out (inside or out) at the property over the last year: new roof / new drains - failure of old drains / demolition of internal walls / felling an old tree / digging-out the flower beds (yes, it can happen with old houses with shallow 'foundations') - it can be a long list, but the starting point should be the basic question to think of anything which has changed recently.....and it can be something as apparently innocent as a neighbour installing rainwater guttering which has chanelled and concentrated water at surface level.......
It may help to think of your house as a simple 'house of cards' (although significantly more complex and solid); where every component of the structure both gives and receives strength and support to the totality; so anything sudden is to be taken seriously; you / your insurers need to consult with appropriately qualified building surveyors / structural engineers.
As an immediate step, you should collect any debris underneath these cracks and keep a careful watch for more falls; stick home-made "tell-tales" across the cracks (a light ribbon / piece of paper;- anything which will break or tear if the cracks enlarge or the walls move) / or place nails into the cracks - if they enlarge, the nails will fall out. Take photographs. Check that all windows and doors are opening and closing easily -differential movement in the frame will induce distortion.
Finally - and not want you'll want to hear at this time of year; consider what you can do in the worst case scenario of feeling physically intimidated by the building and / or the structure being declared unsafe by a qualified professional.
Wishing you all the best, and hoping this is only a minor problem.