How fast did you training the demon seed skills? I was pumping Demon Seed and Bind Demon in early T2 to get more and better seeds, which is part of the reason I had a shortage of class points for Sacrifice.
You can do something like the following by level 20:
Dem Pact (6)
1/5 - this open all slots but only does gives imps. IMPORTANT NOTE: you actually want to stay LOW in the seeds so you ONLY get imps for as long as possible. You the highest Flame bolts and cleansing fire you can get. The more points you put in seeds the more diluted things get. Don't put points into seeds until you have the imps you want and only when you feel the need for Blood Shield and/or corrosive cone
Doom shield (2)
1/1 - you want Osmosis shield and a good block rating and you want armored core, even with one point these are both good. You can put points into the increase these as you feel it helps.
Necro Minions (4)
1/3 - you gotta have this for sac shield
Adv nec min (4)
1/1/2 - you can only put 2 or 3 points into sac shield buy level 20 but it still quite good at this point
1/1/1/1 - you want to armor and you absolutely should run disintegrate for fast digging.
1/-/- - take this at level 10 and put one point in SoL. You eventually want to get more points and you want crusade, but much like doom shield the later points can be done whenever
This is the bare bones skeleton which comes out to 21 points level 20 is what like 25? So you have some leeway to put a few into Hardened core/SoL/Osmo shield/seeds. You will probably fill out seeds by level 30, but not only do you not need to rush seeds it is actively harmful to do so since your two biggest early seeds are fire imps. You need to unlock the body slot though because you need cleansing fire as soon as you can get it.
There are about 2-4 points to mess around with and you can play around with different things depending on various factors: great shield block means Osmo shield may not need a boost, really good armor equipment you can slack on hardened core (and vice versa) etc. Or if you already got some level 4 imps maybe you put 2 points into seeds to get Blood Shield.
Absolutely DO NOT GO TO 5 in seeds until after 30 or even later. 5 in seeds only gives you corrosive cone and you can swap that in later and you need a good enough Flame bolts imps before you can split two different seeds on weapons.
Edit: it took me a restart after a trial run to realize the keeping seeds low trick. Rushing seeds early can really mess you up. However when to get to 3 points for Blood Shield is a much trickier thing. I think I had 3 in seeds by level 20 if I remember right. But while Blood Shield helps and is probably most useful in T2 it is also something can be done without, whereas Sac Shield cannot be done without. It seems conceivable to me that Blood Shield could be delayed until 25 or even 30, but it is possible to go extremely lean and have Blood Shield and Sac Shield together. Really you want to take stock of the 4 defense categories I listed and just shore up whatever is weak or your particular run. You have to have Sac Shield but if your amor is like below 100-150 in T2 then bump armor (hardened core gives most returns usually) instead of bumping seeds and going for Blood shield. Keep an eye on the raw DAM you see in enemies character sheets and shoot to have matching armor, that is more important than Blood Shield and if you are comfortable there then you can choose whether you want to boost your heal or get some dam prevention from blood shield.
In the end I would reccomend not going to 3 points in seeds until you have at least one level 4 Flame bolt seed and one level 4 fire cleansing seed. Since 7 is the max you only need one level 4 FB. Once you have that then weigh out your best options based upon whether you feel Blood shield (probably something around damage soak of 20 for that level ) is worthwhile. Blood Shield is mostly for procs and you may be doing fine with Osmo and SoL already there. You want it later on and it helps early on but its just one factor.