Girlfriend leaving for a month, terrible separation anxiety

My girlfriend of 4 months or so is going away on Sunday to travel around Europe for a month. And I'm feeling awful separation anxiety already - my negative thoughts just keep spiraling and I keep finding myself anxious and having this constant tightness in my chest. Occasionally in the evening I just burst into tears and can't stop crying.

Even though I haven't known her for that long, I can't imagine ever being with anyone else - and she feels exactly the same. It's one of those cases where you just know we're the ones for each other after a few weeks of dating, even though I've always been skeptical of this. I find it fascinating how much she is just like me. Which is why I just can't stand the idea of being without her for a whole month. It just feels like something I can't handle.

I've had separation anxiety in my childhood, I was always worried that something would happen to my mother when she was away. I thought I had gotten over it, but it struck a few weeks back and I can't help but feel absolutely awful. I keep thinking about tomorrow when it's the last day I'm going to see her before she leaves. I keep thinking about how I'm going to miss her voice, her smell, her smile, all these little things I adore about her, everything. I'm afraid that she'll injure herself or something like that during the trip. I keep worrying and thinking of worst-case scenarios that could happen. And it just fills me up with so much fear.

I keep trying to distract myself from these thoughts by doing things I usually do, but eventually my thoughts drift into anxious ones and suddenly I feel like doing nothing at all but just crying and worrying. It makes me happy for me to have found a woman who I want to spend the rest of my life with, but it also tears me apart that I can't stand being away from her. I can't stand how much I'm going to miss her every day, every second. I hate myself for being like this. I've talked to her about this several times, bursting into tears a few times too. She understands me perfectly, but I don't want to keep burdening her about this all the time - I want her to have a fun trip after all. She's similar to me in terms of missing me a whole lot when being away from me and she keeps worrying about me too, but in my case it just fills me with anxiety and dread on top of that.

Just wanted to vent, would like to hear if someone has gone through similar experiences, shares my worries and issues or has any suggestions on how to cope with this. It's just really hard for me and I can't shake this overwhelming feeling of loneliness.

Distraction is good. I have a pet cat so I have company. I don't know if having a pet is possible where you are.
Best of luck to you.

Thank you. I do have two cats, but keeping myself distracted is so hard. Everything just reminds me of her. For the past few days I've woken up and instantly burst out of tears thinking about how I'm not going to see her for a month. I'm just hoping it would get better soon.

A month might seem like a long time but in the meantime try to focus on all the hobbies and interests you might not have had time for when she is around. Treat it like your own vacation. Also this is the 21st century so you can literally see her face every day with Facebook video calls.