What tank your using? What's your exposure protection? Drysuit type and undergarments?
It is common for new cold water divers to struggle with getting down from the surface. You may need to swim down the first 10-15ft. Are you sure you are dumping all the air from the bcd and drysuit?
I was using an AL 80 at first, on those dives I had more buoyancy issues. Switched to a steel tank my last 2 dives and I liked it more, so I think I'll stick with steel. Using a very, very old whites polar flex drysuit. The top is fabric (bilaminate? not sure), and the legs are crushed neoprene with rock boots. 7mm hood, 5mm gloves. Undergarments I tend to wear a wool shirt and leggings under the rented fleece undergarments.
I did learn the very fun lesson during my OW dives that if you wear multiple layers of fleece sweaters, you will be nice and toasty but also a little bit too floaty . . .
It is possible that I'm not dumping all the air from my BCD, I find that air gets a bit stuck in it. It's a wing style, and underwater if I vent it I have to actually roll slightly onto my right side to get the air to travel to the LPI. Will think about that while descending this weekend. The drysuit and I have a love-hate relationship (I love the suit, the suit hates me), and I put very little air in it otherwise it seems to get stuck in my feet, or the air expands before I can vent it while ascending and I'm suddenly at the surface. So I don't think air in the drysuit is contributing too much.
As someone else mentioned, I know that part of difficulty descending is nerves. I think the idea of continuing to exhale for the first 10-15 feet will also be helpful - crazy how much easier it is to stay down than get down.
Very much looking forward to trying weight-checking methods given here and seeing how it feels, thanks again for the help!