first ultrasound at 5 weeks

Is it normal for my HCG levels to be low at 5 weeks? Doctor said mine were 1000 something and that they were low but it’s expected at 5 weeks. Is this true? I’m paranoid now especially because I have a uti that is trying to work it’s way to my kidney and he said this can cause miscarriage. Anyone else’s levels low at 5 weeks 2 days? And does my gestational sac look normal? I feel like it’s smaller than others I’ve seen at 5 weeks. We couldn’t see baby yet. Thank you all in advance.