mccollie,
First trimester bleeding is any vaginal bleeding during the first 3 months of pregnancy. Vaginal bleeding may vary from light spotting to heavy bleeding with clots. Vaginal bleeding is a common problem in early pregnancy, complicating 20%-30% of all pregnancies.
If you are sure that the pink is coming from the vagina and not from the anus, then you should contact your obstetrician. There are many causes of first trimester bleeding, so you should have it checked out.
You do need to treat the constipation. While most people do not think that constipation is much of a problem, it actually is. Constipation is not a benign disorder.
You, of course, need to increase the fiber and water in your diet. But, in addition, you need to take a stool bulker, such as Metamucil (psyllium). You could also benefit from a stool softer such as Senakot-S. While Colace (docusate) is listed as a stool softener, it actually just coats the outside of the stool to make it more slippery, thus easier to pass.
If these measures do not work, then you need to contact your obstetrician for further advice.
Good luck. Hope everything is okay.