Spend some t ime reading around the forum this question has been asked and answered 1000s of times...
it's more than likely water weight gain... food in restaurants has A LOT of sodium in it... and that can cause water retention.
You SHOULD NOT be weighing yourself every day..
Changes in the scale do not mean that you gained fat... just like a 2lb loss overnight doesn't mean you lost 2lbs of fat -it just means the scale changed - fat loss occurs over time...
Get yourself a measuring tape and focus on bi-weekly measurements rather than on daily weighing on the scale...