Crying is okay. Being emotional is okay. Feeling lonely can be really hard.
I wonder if you feel it extra hard due to putting a lot of negative value into being lonely or emotional. Like, do you equate being alone with being a bad person or having failed in some way? A lot of us do. Try to untangle this and not consider loneliness a flaw. It's just a condition, like being cold or warm. It can be uncomfortable, that's it.
I feel lonely sometimes. When I do I read books, particularly fiction. In doing so I get to experience the characters lives and feelings and struggles, and I feel less alone. Riding my bike to the library and perusing my favourite sections or even staying for a read feels like I've done something worthwhile that day.
I have joined book clubs to discuss certain books, and come to appreciate literature where most of it went over my head before. There are clubs online and in person. I prefer in-person because I find it difficult to speak up on mic. Libraries are awesome. As are book/game/culture shops that may arrange themed clubs or events.
Some people with ADHD have trouble reading, audio books are a perfectly valid option. Or any other hobby or activity.
Being in nature is always good for mental health, as is animals. When I had time I volunteered at pet shelters. It feels good to do good. If you have an acquaintance with dogs you can ask if you may join them for a walk or hike next time/next weekend. It will give you a chance to go out and be in nature and spend time with another human. Even if you have nothing to talk about just walking and focusing on a dog and pointing out a strange flower or cool colour is enough. Being in silence in nature is healing. Wear good clothes.
Do you have coworkers you can try small talking with?
People generally like talking about themselves so if you practice asking good follow-up questions you will be able to have long conversations without having to say much yourself. The questions you ask need to be paired with your own enthusiasm though, to make people feel comfortable and confident to keep talking so they don't feel like they're boring you. And eventually to form real connections you need to open up as well and share to make the relationship more equal and let them know you. Hopefully you feel more comfortable talking by then.
Movies, novels, manga, going to the city, walking, people-watching, pets and family are easy topics to connect to others in conversation. Asking someone what they did this weekend or what they do for fun you can probably relate back to some of your own interests, you can mention something about your own preference and then ask follow-up. (-"What did you do this weekend?" -"Laundry, went shopping for presents, bowling, then just relaxed with a movie" -"was it a good movie? What kind of movies do you like?" Or "presents? What are you celebrating?" Or "bowling seems fun, but difficult! Do you go a lot?"). I try to keep small talk to 5-15 min depending on how engaged the other person seems to be, and end it with something positive like "I'd better get back to [work/person/activity], but it was nice talking to you".
Perhaps there is a cat shelter in the area that needs volunteers? Even if you can't bring a cat home you can clean out their habitat, drive them to their homes, wash towels, send out mail, and socialise the cats in the shelter... There's usually a need for any skill. And you can either do your tasks in silence or try to small talk with other people there.