Ok now I can understand why some people hate the dilemma of going to both AT&T and Apple. So Friday morning, I walked in my local Apple store, of course I explained my scenario first and apparently the genius who I was talking to has experienced the same kind of problem with some iPhone users.
So what he did was a diagnostic test on my iPhone (for a couple of minutes) so I patiently waited, after which to my amazement my iPhone was really in top condition, almost no drop calls, strong antenna & signal blah blah (the Genius continues on) and then he goes it's probably some network issues. He told me to drop by an AT&T store which is also within the area, and ask them to do a SIM swap.
So I left the store, went to the AT&T store right. This lady greeted me and I've explained my situation, told her that I was just from the Apple store and again it seems she had this scenario lots and lots of time before because she goes
those people need to be educated, it's not our network, it's their hardware. She kept on going and going, telling me that the SIM swap wouldn't solve the problem, instead you need a new iPhone while along the way I'm confused why these two are pointing each other

So she gives me a new SIM card, replaced my old one and I made sure my contacts were still intact (of course it should be) and she finally bid farewell and good luck.
So right now I have a new SIM card (that lady had tons on her counter apparently being swapped left and right by iPhone customers) and so far it's working fine. I will update any changes or if this doesn't ring problem happens again. I'm still thinking about what happened earlier about those two. The next time this happens again, I'm gonna pull Apple's supervisor and AT&T's supervisor to talk to me with regards to this blame it to someone issue (they're just a few blocks/stores to each other)