Recently, my husband's brother saw a license plate with their late sister's birthdate and initial on. I'm not sure how much I believe in coincidences, but my husband really needed this sign from her and he too believes there is deeper meaning. 

...Anyways onto my main question. Sorry in advance if this is complicated!!! 

Just to preface, I grew up on the east coast (US), attended college out west, and moved back to the east coast (different  state) with my family 5 years ago. Here I met a good friend of mine (I'll call her K) and our kids get along super well. 

Long story short, yesterday I found out that my K's sister-in-law (I'll call her M) was VERY good friends with my older sister in high school and are still friends.

We all went our separate ways after college, but my M married my best friend (K)'s brother. 

K and I had no idea we shared this mutual connection, and what are the odds?

While I think this is really crazy and even brings us closer, I feel like this is just TOO MUCH coincidence. The world seems really small right now, I'm sort of wondering what is going on, all these coincidences lately... Is it normal to be feeling weirded out (like crazy)? 

I guess I just needed somewhere to share this. If you need clarification, let me know and I'll update, but I would like some reassurance. Is it normal to have a big coincidence like this? If you have a story like this, I would really like to hear it. Please convince me that this isn't too crazy.. Thanks.