I'm all positive its going to reach $6k before May. It continues do so since the time it break $5k, I didn't even expect how quickly it got to $5.5k. It may be dumped again but will soon bounce again. I think the rise of BTC is because traders are now dumping altcoins for BTC, the demand goes up and so does the price. A lot are expecting BTC pump but its still not confirm bullrun because altcoins are being left behind here.
I agree with you, there may be many people who move their altcoins to bitcoin so that the price of bitcoin has increased, but I think bitcoin will drop again in the near future, and then bitcoin will rise again in June or July.