Bleeding While on the Ring?

I've been using the Nuvaring for over eight months now. I started off the first three months taking it out after three weeks and replacing it with a new one a week later before I talked to my doctor about skipping my periods. I deal with severe cramps that render me useless as I can't work and usually end up nauseous due to the pain.

Now, I take my ring out after three weeks and put a new one in.

So, I've been using it like this for five months, but a couple of weeks ago, right about a week before I needed to change my ring, I noticed that I was spotting slightly and dealing with my overbearing cramps once again. It's been two weeks since then, I've changed my ring and as today progressed on, I began spotting and suffering with cramps that had me hunched over while I was at work.

I haven't had this happen at all until these past two weeks and I was wondering if this may be a normal thing, or if I should probably go make an appointment to visit my doctor once again? Has anyone had this issue before, and if I need to change my birth control, does anyone have any suggestions on what one would be with low hormones; I'm very bipolar and they had to take me off the pill because it was affecting my mental illness.