Definitely not good. Elongated banana-shaped sacs are usually a sign of stress-induced hermies. If it was me I would be gutted but I would pull them as you are going to end up seeding your whole crop if you don't remove them before the sacs open and release pollen.
I would keep an eye out for nanners also, they are male flowers without the green sac surrounding them. Nanners are like very big and longer pistols. They can release pollen as soon as they form and do not have any sac. Give
this google images link a look and see what to look for.
Get yourself a decent roll of black duct tape (white is better for reflection but may still let light through, but if you use white then layer it till no light shows through) and seal any tiny holes in your area that may let in light and tape up lights on any electrical items inside the grow area too. If you don't have a timer, get one also that can support your light (usually any from a grow shop is good).
If your grow area is a reasonable size for a blackout curtain to cover then throw something like that over it to help block any light leaks.
Whatever happens, don't let it dishearten you. Things like this happen and it will just make you more experienced in how to handle it.