Also, if you took a morning-after pill in February and your period has still not come, rather than take another morning-after pill, take a pregnancy test. As already said, the morning-after pill is not entirely infallible.
Here's some lube without hydroxyethyl cellulose - https://goodcleanlove.com/products/almost-naked-organic-personal-lubricant?variant=8276930166826¤cy=USD&gclid=EAIaIQobChMIi5O4-eHv6AIVk4nICh1tOwXbEAQYASABEgKcnPD_BwE
You didn't answer about the latex - if he can handle balloons or doctors can use latex gloves with him. If he can, you can get non-lubricated latex condoms and use the above lube.
If you can't use those condoms, and you can't use any hormonal contraception, and continue to have unprotected sex, you are going to continue to get pregnant.
The abortion pill is hormonal, though. Is that not making you sick?
I mean I can't use hormonal contraception I forgot to mention that. It makes me sick and not eat sometimes. He's allergic to hydrogyethylcellulose and I'm pretty sure polyurethane has that as well so those are out of the question.
Have you considered getting on birth control? Taking emergency contraception should be reserved for emergencies. It would probably be safer and more economical in the long-run to get on standard birth control. Also, it would help relieve some of the worry and constant thinking about whether you are or are not pregnant.
Are you taking the pills without knowing for sure if you're pregnant? You should take a test first before you start messing with your hormones.
Are you sure your boyfriend is allergic to latex? Can a doctor use latex gloves with him? Can he touch balloons? There are polyurethane condoms that he can use, and there are many of those readily available at most places you can buy condoms. Lubes today are pretty non-irritating.
What ingredient is he allergic to in lubricant?
He may not be ejaculating in you, but pre-cum has sperm in it, and not using birth control or condoms means that you can get pregnant even if he pulls out.
If you all respect and love one another, and yourselves, you'll sit down and have a serious conversation about birth control. If he's sweet and loves you, he won't want you to continue to go through this, and will try some non-latex condoms.