ready to call it quits

hi I'm from the u.p. of michigan. after listening to my hubby for years about chickens I finally gave last spring. we got 12 leghorns (which luckily was all hens) from TSC and 2 Pekin ducks. With the understanding I was only taking care of the ducks, didn't want any part of wing flapping chickens. Welll a year later, the ducks were rehomed due to picking on the hen, no other place to put them over the winter. We never lost one single chick. During the early part of spring say March we lost 2 right in a row. I was able to nurse 2 other back but one never did lay again. Not sure what caused it. So I ordered 3 silkie chicks and 3 olive egger chicks, now this is the woman who wanted no part of chickens. When they finally arrived they had sent 9 chicks, 3 were dead already, 2 more died not long after. This should have been a sign. But I found a local gal selling silkies so I got 7 more. Well since mid summer I have lost 2 leghorn hens, my only olive egger pullet, and 1 silkie pullet. now I have another silkie pullet sick. I am trying everything I can think of. Nothing helps. I am so ready to call it quits!!! Is this a normal part of raising chickens or am I doing something totally wrong? This is breaking my heart like it's my fault they are dying.

So sorry you are having such a rough go of it. The short answer is that, no, in a healthy flock the rate of loss you are experiencing is not normal. You may have one issue or may have had several issues which have contributed to the losses - with a little more information we can try to help you sort that out.
You mentioned nursing some of the original birds back to health after the loss of two others - what treatment course did you use and what symptoms were they showing that you were trying to address? It may be that the initial illness was one of the ones that leaves surviving birds as "carriers" which would leave them able to infect all new birds they are exposed to as you tried adding to the flock. What symptoms are you seeing? Is there discharge from the eyes, nares, vent, beak? Is there a foul odor from either end of the bird? Does the sound of their breathing change? Are they eating and drinking but still losing body mass? What sort of waste are they expelling?
Chicks being lost in shipping is a common issue and is one of the reasons you often find "extras" included in an order as the hatchery is a) providing warmth to the ordered chicks if you place a small order such as your's and b) stacking the deck in favor of you at least getting as many birds as you ordered.

the first hens we lost I am not really sure what was wrong with them. first they had nasty butts, treated them for vent gleet. ,warm baths, yogurt and scrambled eggs, probitotic in water, prep H, antibiotic cream. then it was lethargic birds, soft shelled eggs and bleeding from vent. nothing helped them. treated whole flock for corriditis and now do it monthly, wormed them, and treated for mites. nothing helped, then I read that they could be suffering from mold from using equine pellets for bedding. changed that out and the dying stopped. now it has started again. I still have one of the first birds that had gotten sick, she's blind but gets along ok. still lays. when the olive egger pullet and first silkie pullet died we thought it was having 2 standard size olive egger roosters in with them so they are now in their own pen. this silkie that is sick now is very thin, like the other 2 she got lethargic and had trouble keeping her balance. I can't see anything wring with her. her butt is clean, no discharge anywhere. her crop is empty. she hasn't started laying and I don't feel and bump where she might be egg bound. I feed them all flock pellets, clean water with either natural vinegar, or probiotic in it. scratch and and some sunflower seeds added. chunks of pumpkin once in a while. and I have a flock block outside in their run. and like I said I treat them with corid once a month, I just want to cry I'm so disheartened.