Second time using Ketamine advice

I’m new to ketamine and I want some advice, I'm all about harm reduction and understanding the drug I am taking.

The first time I tried it, it was after a rave where I had done MDMA, 2CB and a bit of cocaine. Once we returned to the hotel with my friends, I did a few bumps and lines and loved it. I slept like a baby. Things were very wonky. This was about a week ago. I did about 2 bumps, followed by 2 50mg lines and then 2 more bumps in the space of about 2-3 hours.

After that, I decided to get some K, from the same guy my friend got his from.

Me and my girlfriend decided to do some K last night. We had about 4-5 bumps in 2 hours, and then decided to mix it with 2CB (I make my nasal spray which delivers ~4mg per spray). I am very familiar with 2CB and I use it often, around 3-4 times a month, usually in social environments like going out etc.

So the 2CB come-up was very intense, nothing like I ever experienced it and it was only 4mg nasally it felt like it was around a 15-20mg nasal come-up, but without the crazy visuals, next time I will do 2CB first and K after.

We waited about an hour and a half after the 2CB to do more K. We did 2 50mg lines spaced about 10-15 minutes apart, which is what sent me to the moon the first time I tried it, however, I didn't feel much at all this time around, however my girlfriend did but also not as much compared to the first time. We did another bump about 10-15 minutes after to I guess "chase the high" and still nothing. I was very confused as to why it wasn't working.

After this, I tried to sleep, however, I felt so AWAKE, sort of a cocaine-like feeling but I felt comfortable in my body whereas the first time I used K, I just fell straight asleep right after I was done, literally like a baby. My girlfriend on the other hand felt sleepy. We did the same doses, the same drugs etc.

I had to take a zopiclone to sleep. To add to this, my girlfriend also tried K the first time with me a week ago and she said it felt very similar to the first time so I don't think the actual K was the problem.

I know tolerance is a thing for K, which I admit, I'm not used to as 2CB doesn't build a tolerance.

I guess my question is, why is the second time so different to my first time?

Why was I wide awake? I understand I did 2cb, but I also did a lot more 2cb the first time I tried it, on top of MDMA and a bit of cocaine.

Why did the 2 50mg lines do nothing to me?

What can I do next time to get it similar to my first experience?

Honestly, any knowledge, or advice is greatly appreciated.