Ive already taken a day off this month. I have work tomorrow but I feel sick about going in. I haven't been able to focus and feel like I haven't been performing that well or that my managers are getting frustrated with me. 

I've only been there 6 months and feel guilty if I take time off (I've only taken two days off in total) but I just feel drained. I started therapy a couple of weeks ago so im trying to work through it but I don't think I can work tomorrow. But im worried my manager will think im lying to take a day off or im just slacking. 

Any advice?