Side effects of the combined pill

Ever since my first pregnancy I have had intermittent but major side effects on the pill.  I gather that this can be more of an issue after hyperemesis and so far it just seems to be a case of trying different pills to see whether I can find one that works.  The odd thing is that I don't get the side effects every month but then other months I would swear I was pregnant!  In a bad month (which has probably only happened two or three times) I get morning sickness that is identical to that of very early pregnancy for me, vomitting and increased sense of smell.  I have had a few days where it is debilitating enough to stay home from work, and a couple of months where I have been concerned enough to get blood tests done even after a couple of poas tests!

I want to stay on some form of contraception and it needs to be pretty cheap (the longer term contraceptive options seem to require several hundred dollars).  I have always found the pill great (apart from this!).  I like the fact that I know where I am at in a cycle and I have no issues with taking it every day etc etc etc.  I also have either endometriosis or idiopathic chronic pelvic pain and the pill has managed this amazingly well for years - so I'm really reluctant just to switch to something else.

So...has anyone else had this sort of experience?  And what have you done in terms of managing it, or changing it?