2 people close to me are pregnant and I am struggling to conceive

So my sister and my first cousin have just told everyone they are pregnant. I am very excited for them! It's awesome, I am, however struggling within a bit because I am struggling to conceive. Well, it's been 7 months of trying.  I am happy for them, it does make me a bit sad, or a lot sad that it's taken me and my hubby so long to conceive. Any advice?