help irregular period nightmare

Hi guys this is my first post so here How's, I've been irregularly bleeding for about two years now. sometimes life gets so busy I just ignore it but last year I came out of a long term relationship and have started seeing some one new. it's getting to me a little as it's so unpredictable. I have things in place that I'm going to get checked for but all major things like stis, smear and general checks have come back not to be the cause. does this sound familiar to anyone else and is there any suggestions? I'm getting embarrassed as I'm scared to do the deed with the new guy in case I bleed.