hi,i read your problem.
you have infection in your teeth which has been reached to roots,in the absence of treatment pus has been formed and pushing your teeth because of that your teeth became loose......
now by sinus
formation this is coming out,so need to get worried.
i will suggest you please go to an endodontic and follow all the given instructions and take after whole mouth examination go for a proper treatment,please do not leave the treatment in between as you will get relieve...........