Found your problem... You're level 40, and the way that Bioware designed this game at release, lvl 40s have no chance of winning against geared 50s. Sorry, that is part of life and you must just accept that.
This games PVP becomes more and more of a joke daily. I hear about a patch coming but I have yet to see any action nearly a month later to fix literally ANYTHING. I cannot stress that point enough, in one months time, NOTHING HAS BEEN FIXED IN PVP.
Sorry, if you want actual PVP I would suggest leaving this game and checking back when some kind of progress is made.