This is clearly a withdrawal sign. Cannabis increases appetite and hence when you stop it abruptly, the reverse happens, ie, the appetite reduces. Anxiety and panic attacks are well known symptoms of cannabis withdrawal. We routinely see clients with these problems. Generally, the anxiety subsides completely in 1-2 weeks while the return of appetite may take 3-4 weeks. If you are finding the anxiety very troublesome, short term use of benzodiazepines such as clonazepam, diazepam etc under expert supervision is immensely helpful. finally, understand that there is nothing to worry about, and congratulations on your decision to quit!