If you really value your friendship with them, then yes! Try to talk to them and see if you can work things out. Sometimes an argument can get blown out of proportion when it was really just a minor disagreement.
You should never feel pressured into sex. Explain to him how you feel. How he responds is an important factor for you to consider in your relationship.
Avoid. The glue will destroy your nails even more. Just paint your nails with regular polish at home, and keep cutting your nails until the damaged part fully grows out.
There's nothing wrong with talking about yourself if your friends are asking you questions. Try turning it around and asking them some questions. When they ask you something, end your...
If you have enough space to invite them to your party, do it! They will probably really appreciate the invitation, and your party can give you a reason to talk...