I am not sure where you bought your bow or what the setting is for it. There should be a sticker on the bow stating what the draw weight range is. Also, I have no idea as to your stature and strength.
From your post I assumed you didn't get your bow from an archery shop - or at least a reputable one. A decent shop would have helped you with all your archery problems you are having. Another thing, just unscrewing the limbs not only changes the draw weight but also the tiller setting. And if the tiller setting is off - which it problably is now, your bow will not shoot as accurately as it should even if you could draw it back.
My guess is you bought a bow that has a draw weight way too heavy for you. If you are young you can get a 35-50# draw weight bow that, set at 40#, will easily kill any whitetail around if you plan on hunting with it. (I shot quite a few deer way back when with a 40# recurve)
I suggest if it is possible, to take it back and get a bow that you can handle or get your money back and go somewhere to someone who can help you make the proper selection.