Going to try Preseed - down in the dumps

Hi everyone
I've caved and decided to try preseed. I'm just getting completely desperate and want to try any thing I can to help . Any feedback, tips on using it would be great! 
Both of my best friends have now announced they are both pregnant and I just keep bursting into tears. I feel horrible - I'm trying to be strong , and although I am completely happy for them , I am worried I'm not hiding my emotions very well as I just feel sad I can't be excited with them and experience this together :( 
Anyone in the same boat? I feel horrible for feeling like this .
The fact that my cycle just seems to be getting longer and longer ( around 40 days) isn't helping :( just feeling very down in the dumps and very alone :( sorry for the negative post ladies , trying to keep it together but there's no one else I can talk to :( xxx