Worried that my girlfriend is hising something from me

I live in Vietnam. I am from the US. My girlfriend(29) is VN, but she lives in Japan (has been for over 10 years). We met in January of this year in Vietnam, and have talked every single day since. Calling on the phone, texting, everything. We get along amazingly well. I finally got to visit her in Japan in May, and we made it official to start a real relationship, although long term (she plans on moving back to to VN next year though).

I went there and everything was amazing. We had a great time together. And she came to VN a few weeks ago and stayed with me for 2 weeks, then another week with her parents. Then she went to the US for a 2-week business trip. She just got back to Vietnam today.

She is a social butterfly. Gets along with everyone. Is gorgeous, everything. She has told me a lot about her past exes and trauma she's been through. Our communication has always been good. She went to an international university, so she has friends all over the world now. Some in the US.

This is where the story gets... interesting.

So, I wanted to find out about her exes, and came across a guy that she has known for at least 4 years. There are pictures of them together in Japan (this guy is from the US--Seattle).

Her business trip was to Seattle, then a couple more cities.

However, last week, I got this weird feeling in my gut. So, I went on fb, and went to the guys fb page, and he happens to be in Seattle (arrived 2 days before she did).

However she had already been there a week at this point. She was super busy with work (she said).

The guy's fb page is very private, so can't see much there.

I randomly found his father's fb page, and went there. Then, I saw a picture of the guy, my girlfriend, and the guy's grandparents at their home. Their arms were behind each other's backs for the photo. But they weren't standing super close to eachother.

I started freaking out. She never told me about this guy. And never told me about meeting a friend from Japan or anything.

So I called and called her. But it was too late there (time difference).

So, I finally talked to her the next morning. Btw the guy's house is like 30 minutes away from Seattle where she said she was working.

I talked to her for only a few minutes, (her sim card is weak and cuts out randsomly), and I asked her that I thought she was working the whole time in Seattle. She said of course she was.

So then, I asked... well, what happened on Tuesday (the day the p

icture was posted). She said what do you mean? (She did'nt sound defensive at all, just genuinly curious).

So then, I said, well, what about Tacoma (where the guy lives)?

Then the phone got disconnected.

I didn't talk to her again for another 12 hours.

She finally messaged me back saying that she doesn't like it when I'm insecure (neither do I.. I hate it). I was at work at the time.

I got home from work, and went to the guy's fb page, and come find that he has now BLOCKED me.

I never told her his name. I only said "Tuesday," and I don't know if she heard me say "Tacoma" or not because the phone disconnected right when I said it.

But, she obviously told him about me. Because I have never talked to this guy before at all.

But now I am blocked by him.

We have talked about other things since then (this was a week ago), but I have been really down and depressed and worrying the past week that maybe she did something with this guy.

I know I sound crazy.

And I hate that I have these feelings of untrustworthiness towards my girlfriend who I LOVE, and she loves me (at least she says so, and seems like she really means it).

I know that spent the night in a cabin with this guy for her birthday last year, but this was before we ever met, but it makes me feel uneasy.

Oh, and she also stopped sending read receipts on WhatsApp last week as well, so I don't know when she's read my texts or not. And we even went a whole 28+ hours without talking, which has never happened before.