Gamerscore gone to zero

Yes, others are losing score too.

It will sort itself out.

Op,no need to spam the forums with your question,i've given you an answer here

forums.xbox.com/.../1911902.aspx

Thank goodness, I thought it was just me!

I'm afraid that there is no way to reset a legitimate gamerscore at all. Gamerscore resets are only given to people who illegitimately modify their gamerscore. When they get their gamerscore reset, however, there are a number
of other consequences:

1) All of the gamerscore will be reset to zero.

2) A person with a gamerscore reset will be permanently branded "Cheater" on your gamertag.

3) All lost gamerscore and achievement are gone forever, and irretrievable.

Gamerscore resets

A gamerscore correction occurs on a player’s Xbox LIVE account when they gain achievements through avoiding gameplay and using external tools. Xbox LIVE is committed to keeping the service free of this type of behavior as it violates the Xbox LIVE Terms
of Use. When abnormal achievement or gamerscore activity is found, Xbox LIVE modifies the gamerscore of players who meet specific and automated criteria.

An Xbox LIVE player who obtains their gamerscore in this abnormal way will:

• Find their gamerscore reset to zero.
• Be unable to regain all previously earned achievements.
• Be labeled as a “cheater” for the community to view.

Although players who are identified by these criteria will start from a zero gamerscore, they will still be able to gain achievements for future games. In other words, we give them another chance to earn future achievements by earning them as other “fair”
players do. The original gamerscore correction remains permanent without any way to appeal.