Segues will not run on IOS 4 now what? I have a project on Xcode and I am pretty beginner so I started designing my code of course using segues and now I realized that this project will only work on IOS 5!

I guess I will give up before I even started! What am I gonna do now? Is there anything I can transform my project to IOS 4? I am so disappointed and wish I didn't have to design for IOS.
Actually the concept of segues was introduced first in iOS5, however it is also stated in the library documentation.

Nevertheless, you can try to create standalone nib files and copy your UI*ViewControls from the storyboard into the nib file(s). Of course you are still not allowed to use segues but you can easily reintroduce IBActions to handle transitions between the views. It's still some effort to migrate, but not an impossible mission.

In order to avoid such a situation, I would suggest you to make a short requirement analysis (functional as well as non functional) before coding.