Reduced immunity during natural menstruation?

[starsburnaway.livejournal.com]

Hello all, I'm posting with a question about the pill and I guess to see if anyone else has had a similar experience. I was on the pill for around twelve years (since the age of fifteen) for heavy, painful periods and acne. Over the last three years I have been prescribed Yasmin which I have found to be very effective. Around four months ago I decided to come off of the pill to give my body a break and to see if my periods and acne would have settled any with age (I'm now 27). My periods were extremely regular after coming off of the pill - the first began after 28 days, the second after 28 days, the third after 31 days and the fourth after 28 days. My periods have been heavier than usual but not as heavy as they were before. However, my skin has gotten noticeabley worse but that's not the issue I'm writing about today.

The issue is that during my second natural period I was floored with a cold. Then during my third natural period I picked up another cold, although not as bad as the month previous. I'm now in the midst of my fourth natural period and I have yet another cold which feels as bad as the first one I picked up. Admittedly my stress levels have been higher due to completing my university degree this month. I have also put on around 20lbs in about eight months and so my BMI is sitting at around 30, which is something I'm currently working on. Is the fact I'm picking up colds during my period every month a coincidence? I'm actually considering going back on the pill if it will prevent this happening for a fourth month. I work full-time and cannot afford time off work, alongside the general inconvenience of becoming unwell.

Information/advice/similar experiences would be most welcome, thank you.