What's the meaning?

of rush here? There are several meanings in the dictionary that fits the context and I'm unsure of which the poster could have meant.

"I obviously was in a very delusional state at that time. I was about 16, broke and found online poker for the first time and within 2 nights of no sleep grinding hu cash with ridic brm I racked up about 4k in debt on mummys card. During these times I felt like I was on crack (not that iv done crack), it was an insane rush even though I wasn't winning. I went to work one day without sleeping for almost 2 days and I wasnt tired at all because I knew poker was waiting for me back home."

Thanks a million!