I'm furious at myself for not purchasing bitcoin sooner. Though I'm a happy man now because I can now smile at my wallet.
Invest now, so you will not regret it later.
You don't have to be mad at yourself for missing an opportunity, it not only happens to you but I believe there will be more than half of the forum members who have missed an opportunity like you including me. You should be angry at yourself if you don't buy bitcoin from now on, because now everything seems so clear and if you miss buying bitcoin again, your mistake is huge.
To be honest, I'd rather invest in bitcoin from now on than before, even though the current bitcoin price is higher but the future is clearer, and the opportunities are clearer as well. And for me, everything has just begun, we're still in its infancy, and there's still a lot of opportunity.