****CATS: please help****?

i am currently pregnant but going under a lot of stress because of my cats. i have to give them away because some of my husband's parents are moving in with us and his mother is extremely allergic to cats. i did my research and called all the rescue groups in my area, posted flyers and asked friends if anyone knew somebody who would be interested, but nobody responded nor interested. my last option is to give them to spca, but the tought of them being in the cage is terrible because they are so playful. i went down to that spca and it seems clean and they said that it is pretty realistic that somebody will adopt them because they've been taken care of. it is 2 cats (boy/girl, brother/sister). they are only 2 years old. i still have them but have to give them up soon. every time i look at their eyes i feel soooooo bad that i have to do this and i ask for their forgivnes. i don't know how to cope with this. i love them soo much but can't keep them. i wanted to know if somebody had any experience similar to mine and how they coped with this? or if you know how my cats will handle the spca and possibly new home? maybe because they are young it would be easier. but i don't know if they will forgive me............ :(