Hey Sleepie,
Before going into full panic mode do a quick assessment of how many calories you've been taking in as opposed to how many you burn a day. I remember saying you bike to work and I know early recovery, for the most part, isn't the best time for a good healthy appetite.
It really may be that simple.
Ask your doctor if a vitamin supplement is a good idea as well. But I stress
ask your doctor.
You're going through enough. Don't make it worse by freaking out over something that may not even be an issue. I know, easier said than done. Buy try!