I got pregnant with a mirena in 5 years ago. It had slipped little into my cervix and stopped working properly - they reckon it happened when I had a smear - pulled on the strings.
Anyway - I was on antidepressants as was still depressed after the birth of the previous two, and had just got over a very painful kidney problem brought on by pregnancy. I needed high doses of painkillers right through the pregnancy.
For us, termination wasn't an option. I had a ghastly pregnancy with 12 hospital admissions and an operation during it, took the antidepressants right through it as well as opiate painkillers and was flown out to a more specialist place (we lived very remote then) for the birth, in case baby had been affected.
She was fine: I was ill for another 2 years with same kidney problem and more serious depression than I had had the last time. When she was born my other 2 children were 3y10m and 1y10m. I was a sahm and it was hard going.
But now ... I have a fabulous extra dd, she is brilliant, wonderful, brings special joy to us and to so many other people. Lots of people comment 'there's just something about her'. Despite the pain and the problems and the illness and hurt, the struggles we had for those 3 years, it has been worth everything because she is amazing. I am just finishing off a 2nd degree and planning on doing a Masters degree next year. She starts school in the Autumn!
I'm not saying this is the option for you ... and I was only 32 when she was born, which is a good 10 years younger than you. But I wanted to tell you my story of an unexpected and unwanted pregnancy, cos mine has a happy ending!
Oh, and dh has had the snip now!!!