Question about taking Unisom with Prenatal Vitamins

I am currently 8 weeks 5 days, I was in the ER for HG because I couldn't keep any fluids or food down. The "morning sickness" seems to last all day and night and makes me so sick I can't leave my bed most the time. My doctor in the ER prescribed me Zofran for nausea, which only was only a bottle of 5 pills because he wanted to see if it worked and to talk to my primary doctor before dosing more (since its not deemed entirely safe for pregnancy) and it worked wonders with getting rid of my sickness for a good 24 hrs and I was able to function normally and eat good. Sadly that medicine isn't entirely safe and can cause birth defects and as it is I feel guilty even taking it at all. Now that I been off it I been back to being sick. Today I bought Unisom Sleep tabs and this is where I am a bit confused because people mention they take it with B6. I am currently on PrePlus multivitamin which does have B6 in it but only 10mg. I read most people take at least 25mg of B6 with Unisom, but with the prenatal vitamins I am on I am not supposed to take more than one a day and I am worried that is not enough B6 to work with the Unisom. I am still going to ask my OB about it, but my appointment isn't until the 17th and I was hoping to relieve myself of the nausea sooner. So my question is would I be OK with taking unisom on the current prenatal I am on? Would it work still? Just want to know your thoughts. Thanks to anyone with some insight!