Should I accept or decline?

I gave my one-week notice, by handing my letter of resignation to my boss and I feel relieved, because I think the hard part is over, yet I've promised my boss to stay for one month further for them to look for the replacement. While waiting the excitement of looking and starting a new job that replace the anxiety of quitting my present job during one month time, my boss messes up me by making me a counteroffer, which slightly a bit higher than what I'm having currently, asking me to reconsider, and telling me that I can expect to learn much more than what I'm doing currently. But what keep me in mind that they are likely to make a counteroffer much more for their benefit than mine. They might be making a counteroffer only to take advantage of me, until they find a cheaper or more dedicated replacement, am I right? Should I stay or should I go? Most of the career advisors advised it’s not a good idea to accept a counteroffer and I agreed so. "Why did they wait until I resigned, to offer me what I’m really worth to them?" I asked myself. And, once I've made it clear that I want to jump ship, my loyalty will be in question to them too. Anyway, I just don't feel like reconsider once I've make up my mind to resign my present job. I think I should land a new job with more pay and growth potential for myself. Am I right?