As has been said above, nobody is ever obliged to leave a single penny to any member of their family. Indeed, the very purpose of writing a will can often be to ensure that the intestacy rules, which would otherwise see the estate going to family members, are NOT applied. (My own will makes it extremely clear that no member of my family will inherit upon my own death).
If you're considering challenging a will you need to decide what grounds you intend to challenge it upon. You can either contest the will as a whole or seek a court order to have its provisions varied.
To contest the will as a whole you'll need to be able to show that one of the reasons listed here applies:
http://www.hughjames.com/service/contested-wills-trusts-and-estates/contesting-a-will/grounds-for-contesting-a-will/
(Although that's a commercial website it still provides an excellent summary of the relevant grounds that may be used to contest a will).
However nothing in what you've written suggest to me that you've got any valid grounds to contest the will as a whole.
To seek a court order varying the provisions of the will (on the grounds that they had failed to make 'reasonable provision' for you) you must be a spouse of the deceased (or a person who was regarded as such by the deceased), a former spouse who has not remarried, a child of the deceased (or a person treated as such by the deceased) or a person who was either wholly or partially maintained by the deceased. Since none of those would appear to apply in your case, I can see valid reason which would enable you to obtain an order varying the provisions of the will.
In short, I think that you'll simply be wasting your time.