Itching, abnormal discharge and a lump?! HELP :(?

Hi, so I'm 19 and for the last 3ish months, I've been experiencing horrible itching just around my oris, nowhere else. My cervical mucus has changed from a normal clear/white and sticky to slightly green/grey and lumpy! The mucus doesn't smell abnormal though. For the first couple of months it would only be like this for about a week or a so before my period started then it would be fine again while on my period and a couple of weeks after. But this month I came off my period last Wednesday and since Friday night it's been back! I keep myself clean down there without messing with the bacteria balance with soaps/douches etc. Also for the last 2wks my left Bartholin gland has swollen to about the size of a biggish marble. I've had an infected Bartholin before about 3yrs ago. This one isn't painful, tender or even uncomfortable. Are these things connected or seperate do you think? Is the itching and mucus issue due to normal thrush? I know that recurring thrush can be a symptom of diabetes and I do already have a risk of developing it as my mum is diabetic as was her dad. Sorry for the long question, but any help really would be great! I have a boyfriend and my problem is very embarring :,(