I'm very sorry to hear of the sad loss of your ex. I haven't experienced this type of event, but I am familar with the feelings of grief that followed when my father passed away. Everyone is different and we react with different intensities, but most people will go through a cycle of shock, disbelief, anger, guilt, sadness (or depression) and finally acceptance. I suffered terribly, felt sick and stopped eating, which resulted in losing quite a bit of weight. My sleeping patterns were all over the place too, which didn't help with regulating moods and I felt physical pain, but Silky was always there to help me through with a comforting hug and a shoulder to cry on. I remember once, being sat on a stone wall in the churchyard at Ashbourne and Chrissie pulled out a spare sock from her handbag, and handed it to me to dry my tears, as I had no tissues left!
I found that long walks in the countryside really helped me to come to terms with my loss and being out in the daylight probably helped too. Don't worry too much about a supressed appetite, as you'll find yourself naturally eating small meals or just a fewer meals instead, but your body won't let you starve - I went down to one or two meals a day, but just follow your bodies natural rhythm with regards to its needs and you'll be OK. This goes for crying too - I found that I cried most when on my own, either when out walking through the fields or when alone in the evening before bedtime. I found crying quite a cathartic and cleansing experience, and I certainly wouldn't advocate bottling up your sadness without some form of outlet.
Bit by bit you'll get stronger. The only other thing I'd say is that going through the grieving process isn't a linear experience. Some days you'll think that you're over the worst and then for seemingly no apparent reason, you'll have a surge of sadness again, which is completely normal. As time goes by as you progress through recovery, the gaps between the sad episodes will be progressively wider. For some people (myself included), it really helps to have someone who can listen to your innermost thoughts, but there are other times when you want to be by yourself to wallow in sadness to help get it out of your system.
If you want to learn more about grieving and how to cope, please click this link: http://www.singlewithkids.co.uk/grief2.htm
. Once on the page, the menu on the left side will take you through the various stages with ideas on how to cope. I think you have a healthy outlook insofar as immersing yourself in Molly's childhood - it will help you both to recover.
Take your time and don't rush your healing. With best wishes,