I know how you feel. I had a lot of bleeding with my first born after years of infertility and pg losses. I was sure that it was all over with every single episode.
I distinctly rememeber the dr. saying that I may be like on of her patients who just bled throughout the whole pg. I was not looking forward to that and indeed the bleeding stopped somewhere early in the second tri.
This is a common time for bleeding in ANY pg. I have no experience with twins but I can only imagine that it must be even more common with multiples.
I wish you the best of luck and will keep you in my thoughts for after all the heartache, you deserve this healthy and full term pregnancy.
Hang in there and use positive affirmations to get through it because unfortunately, achieving pg is not a clear path to motherhood. Those of us, like you, who have walked the IF journey, somehow suffer through the different stages, unlike those who have not walked that journey. We are always aware of the difficult side of things and can never relax and be blissful like those who become mothers in innocence/ignorance.
My heart goes out to you and I wish you the strength to stay positive and hopeful that you are just one of those women who "may" have episodes throughout your pg, but will, in the end, have two healthy take home babies.