1stly China-Pakistan relationship no doubt is great, but as you said, "If U can trade with anyone, that country would surely be in good terms with U. Sides are only taken during conflicts." and we all know what happened in 71. Before that, infact till 90s, pakistan was at par with India, or i should say more than India, but as years passed its deteriorated. I don't want to further comment on your relations, its your internal matter.First of all the history of Pak-China relationship dates back to 1947. We have engaged with each other in every sphere amicably. China had helped us even during the US embargo times and is helping us in energy sector for quite sometime. This much of time of mutual relations is enough to judge the level of friendship and intentions of each other.
Secondly CPEC is just a short route for Chinese products in and out of China. Its not a trade deal whereas China would be flooding our markets with each and everything. If say our textile, sports goods, agriculture etc sector produce stuff that is worth exporting then we shud surely not import these already available things from China. But yes U r right that if we open market for all Chinese products then we are doomed.
Ofcourse we have our own cards and those can play a balancing factor anyways. Other than China countries like Turkey, Azerbaijan and even Saudi Arabia (and its influence in GCC) are the ones Pakistan can mobilize for that reason.
2ndly, china has a bad habit of dumping, they do it in India and all over the world, what makes you think they wont? they will never invest somewhere where there is no profit. Here recently, they backed out of a coal-based project : http://www.dawn.com/news/1259048/chinese-firm-bows-out-of-coal-based-power-project
3rdly, yes, you have cards to play, but then i said "anti-india", Turkey is a nato-ally, SA and India have great relations both in terms of trade and now slowly into defence. Recently i have seen a joint exercise is happening after the red flag exercise. Azerbaizan, probably will support you, but then they are also close to israel, how much can they help i have no idea. Do tell me how many points i said you agree and disagree without being biased.