Sick of this anxiety

Patient: I suffer from anxiety and just started taking it 8weeks ago had a rough start with side effects but most went away but it makes me so sleepy i feel i need alittle more but im on 50mg in the am and 50mg pm and afraid to have my dose upped i have this burning across my chest and under my armpits would this be a side effect from the med or anxiety and i read it takes effexor 12weeks to work if taken for anxiety is this true