i need advice

My entire life is about to change. Last time something like this happened i feel in a deep depression and it was so hard to get out of it.

The first time was around two years ago, i had just graduated, and started a demanding job and new school course, all my friends had left to start their lifes, and my partner started in the army and was unreachably away for 8 months. I was so overwhelmed with all the new things that I got to the point to where I didnt recognize the girl in the mirror literally. I was going through an out of body experience and I didnt tell anyone.

Now im am less than 3 months away from getting married moving across the country, and its a secret because he wants to make a traditional proposal and he's deployed at the moment. everything is about to happen so quickly and all at once. I want the change, and we both have been planning it for almost a year now, and fast past wedding planning is normal when it involves the military. This is thefirst big decision i have made on my own. and im terrified