Macro for transposing multiple columns into a single row

Hello.

I read a thread that included a macro similar to what I am needing to do. However, my data is formatted slightly different. I've attached an example of a before and after of what the data should look like. There are approximately 2700 rows on my actual worksheet...

Any help would be greatly appreciated. I'm not very familiar with macros yet and don't really have a great idea of where to start.

Thanks!