Hi, I'm a 4th year (writing up stage) PhD - and if it’s any consolation, I still feel unsure sometimes. Most phd’s feel like this at some point! But, if you Really don’t know what you're doing a PhD for and you’re only in your first year, than a PhD probably isn't for you. There are good websites (check out the excellent - now defunct -'invisible adjunct') that can give you an honest viewpoint. I would warn against Anyone doing a PhD with no funding though (esp if you are not 150% committed).