hugs im so sorry hun, i know how rough it is seeing a thriving baby with a good strong heartbeat then lossing her. i too had 3 perfectly healhty babies, i had 2 miscarriages but very early on and i never saw a heartbeat. then we had a 4th then surprise we got pregnant with a 5th when the 4th was just 10 weeks old. i made it to 22 weeks and my water broke and i went into labor. no idea why, they think maybe my fluid got infected somehow and my body just pushed everything out to keep me from getting sick but along with all the fluid it pushed out my baby girl too. she lived for 2 hours and she was so tiny and perfect just like your little girl.
i spent alot of time talking to a therapist. it did help alot. she saw alot of ladies who went through miscarriages and still births and infant deaths. i know how much it hurts now and no you won't ever forget her. but time helps, spending time with your surviving children and remembering how precious they are helps. and i promise you will probably get pregnant again when you are ready. i did. i probably did it too soon but i felt i needed to get pregnant again asap. and yes while i did have another adorable little daughter i love so much she can never replace her sister. it will happen for you too. how far along were you? hugs and again im so sorry, allow yourself some time to grieve.