I just started taking Truvada for PREP against HIV. I have been on it for 10 days and for the past 5 or 6 days I ve been very tired. My sleep schedule is a bit all over the place, but that s actually normal for me. I once had to take PEP after HIV exposure and I remember feeling extremely tired and sick for about the first week or so that I was on that (a 30 day treatment). I feel like its just the new medication settling into my system but I also see tiredness as a sign of lactic acid buildup, which can be fatal. Any advice would be helpful!